Die gemeinsame Plattform ist jetzt softwareseitig deutlich vollständiger. Der Host-Core hat mit [show_store.rs](</C:/Users/janni/Documents/RFP/Infinity_Vis _Rust/crates/infinity_host/src/show_store.rs>) eine echte Runtime-Bibliothek und Persistenz für aktive Szene, Runtime-Presets, Runtime-Gruppen und kreative Varianten bekommen; die Simulation in [simulation.rs](</C:/Users/janni/Documents/RFP/Infinity_Vis _Rust/crates/infinity_host/src/simulation.rs>) liefert jetzt typisierte Command-Ergebnisse, saubere Fehlercodes und persistiert nach data/runtime_state.json. Dazu kommt das generische External-Show-Control-Interface in [external_control.rs](</C:/Users/janni/Documents/RFP/Infinity_Vis _Rust/crates/infinity_host/src/external_control.rs>), damit spätere Adapter nur auf definierte Commands und Snapshot-/Preset-/Parameter-Flächen zugreifen.

Die API v1 ist als Produktgrenze geschärft in [dto.rs](</C:/Users/janni/Documents/RFP/Infinity_Vis _Rust/crates/infinity_host_api/src/dto.rs>) und [server.rs](</C:/Users/janni/Documents/RFP/Infinity_Vis _Rust/crates/infinity_host_api/src/server.rs>): getrennte Modelle für `state`, `preview`, `snapshot`, `command response`, `event stream` und stabile Fehlerobjekte mit echten Codes statt generischem Fallback. Dazu kamen `GET /api/v1/state` und `GET /api/v1/preview`, neue persistenzbezogene Commands wie `save_preset`, `save_creative_snapshot`, `recall_creative_snapshot`, `set_transition_style` und `upsert_group`, plus serverseitige Durchreichung der echten Fehlercodes. Die kreative Web-UI in [index.html](</C:/Users/janni/Documents/RFP/Infinity_Vis _Rust/web/v1/index.html>), [app.js](</C:/Users/janni/Documents/RFP/Infinity_Vis _Rust/web/v1/app.js>) und [styles.css](</C:/Users/janni/Documents/RFP/Infinity_Vis _Rust/web/v1/styles.css>) nutzt jetzt genau diese API für Preset-Speichern/Überschreiben, Varianten, Transition-Style, filterbaren Eventfeed und klarere Preview-Darstellung, ohne Parallelarchitektur.

Die Doku ist auf den neuen Stand gezogen in [docs/host_api.md](</C:/Users/janni/Documents/RFP/Infinity_Vis _Rust/docs/host_api.md>), [README.md](</C:/Users/janni/Documents/RFP/Infinity_Vis _Rust/README.md>), [docs/build_and_deploy.md](</C:/Users/janni/Documents/RFP/Infinity_Vis _Rust/docs/build_and_deploy.md>) und [docs/architecture.md](</C:/Users/janni/Documents/RFP/Infinity_Vis _Rust/docs/architecture.md>). Verifiziert habe ich `cargo check -q` und `cargo test -q`; dabei laufen die erweiterten Contract- und Persistenztests in [contract.rs](</C:/Users/janni/Documents/RFP/Infinity_Vis _Rust/crates/infinity_host_api/tests/contract.rs>) sowie neue Core-Tests in [show_store.rs](</C:/Users/janni/Documents/RFP/Infinity_Vis _Rust/crates/infinity_host/src/show_store.rs>) und [simulation.rs](</C:/Users/janni/Documents/RFP/Infinity_Vis _Rust/crates/infinity_host/src/simulation.rs>). Nicht separat verifiziert habe ich einen echten Browserlauf der Web-UI; die JS-Datei wurde hier nicht mit `node` geprüft, weil `node` in dieser Umgebung nicht installiert ist.

Cargo.lock

@@ -1706,6 +1706,7 @@ dependencies = [
  "infinity_protocol",
  "serde",
  "serde_json",
+ "thiserror 1.0.69",
 ]
 
 [[package]]

README.md

@@ -34,7 +34,7 @@ The current baseline is intentionally strict about unresolved hardware facts. `U
 2. Review the open validation checklist in [docs/validation_open_points.md](docs/validation_open_points.md).
 3. Start from [config/project.example.toml](config/project.example.toml).
 4. Inspect the software-first host snapshot with `cargo run -p infinity_host -- snapshot --config config/project.example.toml`.
-5. Start the versioned host API plus creative web UI with `cargo run -p infinity_host_api -- --config config/project.example.toml --bind 127.0.0.1:9001`.
+5. Start the versioned host API plus creative web UI with `cargo run -p infinity_host_api -- --config config/project.example.toml --bind 127.0.0.1:9001 --runtime-state data/runtime_state.json`.
 6. Open `http://127.0.0.1:9001/` for the creative surface.
 7. Start the engineering GUI with `cargo run -p infinity_host_ui`.
 8. Use the host CLI to validate the project config before attempting activation.

crates/infinity_host/Cargo.toml

@@ -9,5 +9,6 @@ authors.workspace = true
 clap.workspace = true
 serde.workspace = true
 serde_json.workspace = true
+thiserror.workspace = true
 infinity_config = { path = "../infinity_config" }
 infinity_protocol = { path = "../infinity_protocol" }

crates/infinity_host/src/control.rs

@@ -34,6 +34,7 @@ pub struct GlobalControlSnapshot {
     pub selected_pattern: String,
     pub selected_group: Option<String>,
     pub transition_duration_ms: u32,
+    pub transition_style: SceneTransitionStyle,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
@@ -52,6 +53,7 @@ pub struct CatalogSnapshot {
     pub patterns: Vec<PatternDefinition>,
     pub presets: Vec<PresetSummary>,
     pub groups: Vec<GroupSummary>,
+    pub creative_snapshots: Vec<CreativeSnapshotSummary>,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
@@ -62,12 +64,21 @@ pub struct PatternDefinition {
     pub parameters: Vec<SceneParameterSpec>,
 }
 
+#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
+#[serde(rename_all = "snake_case")]
+pub enum CatalogSource {
+    BuiltIn,
+    RuntimeUser,
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
 pub struct PresetSummary {
     pub preset_id: String,
     pub pattern_id: String,
     pub target_group: Option<String>,
     pub transition_duration_ms: u32,
+    pub transition_style: SceneTransitionStyle,
+    pub source: CatalogSource,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
@@ -75,6 +86,18 @@ pub struct GroupSummary {
     pub group_id: String,
     pub member_count: usize,
     pub tags: Vec<String>,
+    pub source: CatalogSource,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
+pub struct CreativeSnapshotSummary {
+    pub snapshot_id: String,
+    pub label: Option<String>,
+    pub pattern_id: String,
+    pub target_group: Option<String>,
+    pub transition_duration_ms: u32,
+    pub transition_style: SceneTransitionStyle,
+    pub saved_at_unix_ms: u64,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
@@ -195,9 +218,19 @@ pub struct PanelSnapshot {
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
 pub struct StatusEvent {
     pub at_millis: u64,
+    pub kind: StatusEventKind,
+    pub code: Option<String>,
     pub message: String,
 }
 
+#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
+#[serde(rename_all = "snake_case")]
+pub enum StatusEventKind {
+    Info,
+    Warning,
+    Error,
+}
+
 #[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
 #[serde(rename_all = "snake_case")]
 pub enum NodeConnectionState {
@@ -229,10 +262,29 @@ pub enum HostCommand {
         value: SceneParameterValue,
     },
     SetTransitionDurationMs(u32),
+    SetTransitionStyle(SceneTransitionStyle),
     TriggerPanelTest {
         target: PanelTarget,
         pattern: TestPatternKind,
     },
+    SavePreset {
+        preset_id: String,
+        overwrite: bool,
+    },
+    SaveCreativeSnapshot {
+        snapshot_id: String,
+        label: Option<String>,
+        overwrite: bool,
+    },
+    RecallCreativeSnapshot {
+        snapshot_id: String,
+    },
+    UpsertGroup {
+        group_id: String,
+        tags: Vec<String>,
+        members: Vec<PanelTarget>,
+        overwrite: bool,
+    },
 }
 
 #[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
@@ -241,9 +293,21 @@ pub enum TestPatternKind {
     WalkingPixel106,
 }
 
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
+pub struct CommandOutcome {
+    pub generated_at_millis: u64,
+    pub summary: String,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
+pub struct HostCommandError {
+    pub code: String,
+    pub message: String,
+}
+
 pub trait HostApiPort: Send + Sync {
     fn snapshot(&self) -> HostSnapshot;
-    fn send_command(&self, command: HostCommand);
+    fn send_command(&self, command: HostCommand) -> Result<CommandOutcome, HostCommandError>;
 }
 
 pub trait HostUiPort: HostApiPort {}
@@ -260,6 +324,35 @@ impl NodeConnectionState {
     }
 }
 
+impl SceneTransitionStyle {
+    pub fn label(self) -> &'static str {
+        match self {
+            Self::Snap => "snap",
+            Self::Crossfade => "crossfade",
+            Self::Chase => "chase",
+        }
+    }
+}
+
+impl CatalogSource {
+    pub fn label(self) -> &'static str {
+        match self {
+            Self::BuiltIn => "built_in",
+            Self::RuntimeUser => "runtime_user",
+        }
+    }
+}
+
+impl StatusEventKind {
+    pub fn label(self) -> &'static str {
+        match self {
+            Self::Info => "info",
+            Self::Warning => "warning",
+            Self::Error => "error",
+        }
+    }
+}
+
 impl TestPatternKind {
     pub fn label(self) -> &'static str {
         match self {
@@ -287,3 +380,12 @@ impl SceneParameterValue {
         Self::Text(value.into())
     }
 }
+
+impl HostCommandError {
+    pub fn new(code: impl Into<String>, message: impl Into<String>) -> Self {
+        Self {
+            code: code.into(),
+            message: message.into(),
+        }
+    }
+}

crates/infinity_host/src/external_control.rs

@@ -0,0 +1,124 @@
+use crate::{
+    CommandOutcome, HostApiPort, HostCommand, HostCommandError, HostSnapshot, PanelTarget,
+    SceneParameterValue, SceneTransitionStyle,
+};
+use serde::{Deserialize, Serialize};
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+#[serde(rename_all = "snake_case", tag = "action", content = "payload")]
+pub enum ExternalControlAction {
+    SetBlackout {
+        enabled: bool,
+    },
+    SetMasterBrightness {
+        value: f32,
+    },
+    SelectPattern {
+        pattern_id: String,
+    },
+    RecallPreset {
+        preset_id: String,
+    },
+    SelectGroup {
+        group_id: Option<String>,
+    },
+    SetSceneParameter {
+        key: String,
+        value: SceneParameterValue,
+    },
+    SetTransitionConfig {
+        duration_ms: u32,
+        style: SceneTransitionStyle,
+    },
+    RecallCreativeSnapshot {
+        snapshot_id: String,
+    },
+    TriggerPanelTest {
+        target: PanelTarget,
+    },
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
+pub struct ExternalAdapterCapabilities {
+    pub supports_group_targeting: bool,
+    pub supports_preset_recall: bool,
+    pub supports_parameter_updates: bool,
+    pub supports_transition_config: bool,
+    pub supports_panel_tests: bool,
+}
+
+impl Default for ExternalAdapterCapabilities {
+    fn default() -> Self {
+        Self {
+            supports_group_targeting: true,
+            supports_preset_recall: true,
+            supports_parameter_updates: true,
+            supports_transition_config: true,
+            supports_panel_tests: false,
+        }
+    }
+}
+
+pub trait ExternalShowControlPort: Send + Sync {
+    fn snapshot(&self) -> HostSnapshot;
+    fn execute_action(
+        &self,
+        action: ExternalControlAction,
+    ) -> Result<CommandOutcome, HostCommandError>;
+}
+
+pub trait ExternalShowControlAdapter: Send {
+    fn adapter_id(&self) -> &str;
+    fn capabilities(&self) -> ExternalAdapterCapabilities {
+        ExternalAdapterCapabilities::default()
+    }
+    fn translate(
+        &mut self,
+        action: ExternalControlAction,
+    ) -> Result<Vec<HostCommand>, HostCommandError>;
+}
+
+impl<T: HostApiPort + ?Sized> ExternalShowControlPort for T {
+    fn snapshot(&self) -> HostSnapshot {
+        HostApiPort::snapshot(self)
+    }
+
+    fn execute_action(
+        &self,
+        action: ExternalControlAction,
+    ) -> Result<CommandOutcome, HostCommandError> {
+        match action {
+            ExternalControlAction::SetBlackout { enabled } => {
+                self.send_command(HostCommand::SetBlackout(enabled))
+            }
+            ExternalControlAction::SetMasterBrightness { value } => {
+                self.send_command(HostCommand::SetMasterBrightness(value))
+            }
+            ExternalControlAction::SelectPattern { pattern_id } => {
+                self.send_command(HostCommand::SelectPattern(pattern_id))
+            }
+            ExternalControlAction::RecallPreset { preset_id } => {
+                self.send_command(HostCommand::RecallPreset { preset_id })
+            }
+            ExternalControlAction::SelectGroup { group_id } => {
+                self.send_command(HostCommand::SelectGroup { group_id })
+            }
+            ExternalControlAction::SetSceneParameter { key, value } => {
+                self.send_command(HostCommand::SetSceneParameter { key, value })
+            }
+            ExternalControlAction::SetTransitionConfig { duration_ms, style } => {
+                self.send_command(HostCommand::SetTransitionDurationMs(duration_ms))?;
+                self.send_command(HostCommand::SetTransitionStyle(style))
+            }
+            ExternalControlAction::RecallCreativeSnapshot { snapshot_id } => {
+                self.send_command(HostCommand::RecallCreativeSnapshot { snapshot_id })
+            }
+            ExternalControlAction::TriggerPanelTest { target } => {
+                self.send_command(HostCommand::TriggerPanelTest {
+                    target,
+                    pattern: crate::TestPatternKind::WalkingPixel106,
+                })
+            }
+        }
+    }
+}

crates/infinity_host/src/lib.rs

@@ -1,9 +1,13 @@
 pub mod control;
 pub mod runtime;
 pub mod scene;
+pub mod show_store;
 pub mod simulation;
+pub mod external_control;
 
 pub use control::*;
+pub use external_control::*;
 pub use runtime::*;
 pub use scene::*;
+pub use show_store::*;
 pub use simulation::*;

crates/infinity_host/src/scene.rs

@@ -1,9 +1,10 @@
 use crate::control::{
-    ActiveSceneSnapshot, CatalogSnapshot, GroupSummary, PatternDefinition, PresetSummary,
-    SceneParameterKind, SceneParameterSpec, SceneParameterState, SceneParameterValue,
-    SceneTransitionStyle, TransitionSnapshot,
+    ActiveSceneSnapshot, CatalogSnapshot, CatalogSource, GroupSummary, PatternDefinition,
+    PresetSummary, SceneParameterKind, SceneParameterSpec, SceneParameterState,
+    SceneParameterValue, SceneTransitionStyle, TransitionSnapshot,
 };
 use infinity_config::{PanelPosition, PresetConfig, ProjectConfig};
+use serde::{Deserialize, Serialize};
 use std::{
     collections::{BTreeMap, BTreeSet},
     hash::{Hash, Hasher},
@@ -12,7 +13,7 @@ use std::{
 
 const DEFAULT_SAMPLE_LED_COUNT: usize = 6;
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
 pub struct SceneRuntime {
     pub preset_id: Option<String>,
     pub pattern_id: String,
@@ -70,6 +71,8 @@ impl PatternRegistry {
                     pattern_id: preset.scene.effect.clone(),
                     target_group: preset.target_group.clone(),
                     transition_duration_ms: preset.transition_ms,
+                    transition_style: transition_style_from_duration(preset.transition_ms),
+                    source: CatalogSource::BuiltIn,
                 })
                 .collect(),
             groups: project
@@ -80,8 +83,10 @@ impl PatternRegistry {
                     group_id: group.group_id.clone(),
                     member_count: group.members.len(),
                     tags: group.tags.clone(),
+                    source: CatalogSource::BuiltIn,
                 })
                 .collect(),
+            creative_snapshots: Vec::new(),
         }
     }
 
@@ -102,6 +107,10 @@ impl PatternRegistry {
             })
     }
 
+    pub fn pattern_definitions(&self) -> Vec<PatternDefinition> {
+        self.definitions.values().cloned().collect()
+    }
+
     pub fn scene_from_preset_id(&self, project: &ProjectConfig, preset_id: &str) -> Option<SceneRuntime> {
         project
             .presets
@@ -246,7 +255,7 @@ impl PatternRegistry {
         }
     }
 
-    fn scene_from_preset(&self, preset: &PresetConfig) -> SceneRuntime {
+    pub fn scene_from_preset_config(&self, preset: &PresetConfig) -> SceneRuntime {
         let mut scene = self.scene_for_pattern(
             &preset.scene.effect,
             Some(preset.preset_id.clone()),
@@ -264,6 +273,10 @@ impl PatternRegistry {
         scene
     }
 
+    fn scene_from_preset(&self, preset: &PresetConfig) -> SceneRuntime {
+        self.scene_from_preset_config(preset)
+    }
+
     fn definition_or_default(&self, pattern_id: &str) -> &PatternDefinition {
         self.definitions
             .get(pattern_id)

crates/infinity_host/src/show_store.rs

@@ -0,0 +1,605 @@
+use crate::{
+    control::{
+        CatalogSnapshot, CatalogSource, CreativeSnapshotSummary, GroupSummary, HostCommandError,
+        PanelTarget, PresetSummary, SceneTransitionStyle,
+    },
+    scene::{SceneRuntime, PatternRegistry},
+};
+use infinity_config::{PanelPosition, ProjectConfig};
+use serde::{Deserialize, Serialize};
+use std::{
+    collections::{BTreeMap, BTreeSet},
+    fs,
+    path::{Path, PathBuf},
+    time::{SystemTime, UNIX_EPOCH},
+};
+
+pub const RUNTIME_STATE_SCHEMA_VERSION: u16 = 1;
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+pub struct StoredPreset {
+    pub preset_id: String,
+    pub scene: SceneRuntime,
+    pub transition_duration_ms: u32,
+    pub transition_style: SceneTransitionStyle,
+    pub source: CatalogSource,
+    pub updated_at_unix_ms: Option<u64>,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
+pub struct StoredGroup {
+    pub group_id: String,
+    pub tags: Vec<String>,
+    pub members: Vec<PanelTarget>,
+    pub source: CatalogSource,
+    pub updated_at_unix_ms: Option<u64>,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+pub struct StoredCreativeSnapshot {
+    pub snapshot_id: String,
+    pub label: Option<String>,
+    pub scene: SceneRuntime,
+    pub transition_duration_ms: u32,
+    pub transition_style: SceneTransitionStyle,
+    pub saved_at_unix_ms: u64,
+    pub source_preset_id: Option<String>,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+pub struct PersistedGlobalState {
+    pub blackout: bool,
+    pub master_brightness: f32,
+    pub transition_duration_ms: u32,
+    pub transition_style: SceneTransitionStyle,
+}
+
+impl Default for PersistedGlobalState {
+    fn default() -> Self {
+        Self {
+            blackout: false,
+            master_brightness: 0.20,
+            transition_duration_ms: 150,
+            transition_style: SceneTransitionStyle::Crossfade,
+        }
+    }
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Default)]
+pub struct PersistedRuntimeState {
+    pub active_scene: Option<SceneRuntime>,
+    pub global: PersistedGlobalState,
+    pub user_presets: Vec<StoredPreset>,
+    pub user_groups: Vec<StoredGroup>,
+    pub creative_snapshots: Vec<StoredCreativeSnapshot>,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+struct RuntimeStateEnvelope {
+    schema_version: u16,
+    saved_at_unix_ms: u64,
+    runtime: PersistedRuntimeState,
+}
+
+#[derive(Debug, Clone)]
+pub struct RuntimeStateStorage {
+    path: PathBuf,
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum ShowStoreError {
+    #[error("runtime state I/O failed: {0}")]
+    Io(#[from] std::io::Error),
+    #[error("runtime state parse failed: {0}")]
+    Parse(#[from] serde_json::Error),
+    #[error("{0}")]
+    Validation(String),
+}
+
+#[derive(Debug, Clone, Default)]
+pub struct ShowStore {
+    presets: Vec<StoredPreset>,
+    groups: Vec<StoredGroup>,
+    creative_snapshots: Vec<StoredCreativeSnapshot>,
+}
+
+impl RuntimeStateStorage {
+    pub fn new(path: impl Into<PathBuf>) -> Self {
+        Self { path: path.into() }
+    }
+
+    pub fn path(&self) -> &Path {
+        &self.path
+    }
+
+    pub fn load(&self) -> Result<PersistedRuntimeState, ShowStoreError> {
+        if !self.path.exists() {
+            return Ok(PersistedRuntimeState::default());
+        }
+
+        let raw = fs::read_to_string(&self.path)?;
+        let envelope = serde_json::from_str::<RuntimeStateEnvelope>(&raw)?;
+        if envelope.schema_version != RUNTIME_STATE_SCHEMA_VERSION {
+            return Err(ShowStoreError::Validation(format!(
+                "unsupported runtime state schema version {} at {}",
+                envelope.schema_version,
+                self.path.display()
+            )));
+        }
+
+        Ok(envelope.runtime)
+    }
+
+    pub fn save(&self, runtime: &PersistedRuntimeState) -> Result<(), ShowStoreError> {
+        if let Some(parent) = self.path.parent() {
+            fs::create_dir_all(parent)?;
+        }
+
+        let envelope = RuntimeStateEnvelope {
+            schema_version: RUNTIME_STATE_SCHEMA_VERSION,
+            saved_at_unix_ms: now_unix_ms(),
+            runtime: runtime.clone(),
+        };
+        let payload = serde_json::to_string_pretty(&envelope)?;
+        fs::write(&self.path, payload)?;
+        Ok(())
+    }
+}
+
+impl ShowStore {
+    pub fn from_project(project: &ProjectConfig, registry: &PatternRegistry) -> Self {
+        let presets = project
+            .presets
+            .iter()
+            .map(|preset| StoredPreset {
+                preset_id: preset.preset_id.clone(),
+                scene: registry.scene_from_preset_config(preset),
+                transition_duration_ms: preset.transition_ms,
+                transition_style: crate::scene::transition_style_from_duration(preset.transition_ms),
+                source: CatalogSource::BuiltIn,
+                updated_at_unix_ms: None,
+            })
+            .collect::<Vec<_>>();
+
+        let groups = project
+            .topology
+            .groups
+            .iter()
+            .map(|group| StoredGroup {
+                group_id: group.group_id.clone(),
+                tags: group.tags.clone(),
+                members: group
+                    .members
+                    .iter()
+                    .map(|member| PanelTarget {
+                        node_id: member.node_id.clone(),
+                        panel_position: member.panel_position.clone(),
+                    })
+                    .collect(),
+                source: CatalogSource::BuiltIn,
+                updated_at_unix_ms: None,
+            })
+            .collect::<Vec<_>>();
+
+        Self {
+            presets,
+            groups,
+            creative_snapshots: Vec::new(),
+        }
+    }
+
+    pub fn apply_persisted(&mut self, runtime: PersistedRuntimeState) {
+        for preset in runtime.user_presets {
+            replace_or_append_by(&mut self.presets, preset, |left, right| {
+                left.preset_id == right.preset_id
+            });
+        }
+
+        for group in runtime.user_groups {
+            replace_or_append_by(&mut self.groups, group, |left, right| {
+                left.group_id == right.group_id
+            });
+        }
+
+        self.creative_snapshots = runtime.creative_snapshots;
+    }
+
+    pub fn catalog(&self, registry: &PatternRegistry) -> CatalogSnapshot {
+        CatalogSnapshot {
+            patterns: registry.pattern_definitions(),
+            presets: self
+                .presets
+                .iter()
+                .map(|preset| PresetSummary {
+                    preset_id: preset.preset_id.clone(),
+                    pattern_id: preset.scene.pattern_id.clone(),
+                    target_group: preset.scene.target_group.clone(),
+                    transition_duration_ms: preset.transition_duration_ms,
+                    transition_style: preset.transition_style,
+                    source: preset.source,
+                })
+                .collect(),
+            groups: self
+                .groups
+                .iter()
+                .map(|group| GroupSummary {
+                    group_id: group.group_id.clone(),
+                    member_count: group.members.len(),
+                    tags: group.tags.clone(),
+                    source: group.source,
+                })
+                .collect(),
+            creative_snapshots: self
+                .creative_snapshots
+                .iter()
+                .map(|snapshot| CreativeSnapshotSummary {
+                    snapshot_id: snapshot.snapshot_id.clone(),
+                    label: snapshot.label.clone(),
+                    pattern_id: snapshot.scene.pattern_id.clone(),
+                    target_group: snapshot.scene.target_group.clone(),
+                    transition_duration_ms: snapshot.transition_duration_ms,
+                    transition_style: snapshot.transition_style,
+                    saved_at_unix_ms: snapshot.saved_at_unix_ms,
+                })
+                .collect(),
+        }
+    }
+
+    pub fn initial_scene(&self, registry: &PatternRegistry) -> SceneRuntime {
+        self.presets
+            .first()
+            .map(|preset| preset.scene.clone())
+            .unwrap_or_else(|| {
+                registry.scene_for_pattern(
+                    "solid_color",
+                    Some("bootstrap-solid-color".to_string()),
+                    None,
+                    1,
+                    vec!["#ffffff".to_string()],
+                    false,
+                )
+            })
+    }
+
+    pub fn available_patterns(&self, registry: &PatternRegistry) -> Vec<String> {
+        registry
+            .pattern_definitions()
+            .into_iter()
+            .map(|pattern| pattern.pattern_id)
+            .collect()
+    }
+
+    pub fn scene_from_preset_id(&self, preset_id: &str) -> Option<SceneRuntime> {
+        self.presets
+            .iter()
+            .find(|preset| preset.preset_id == preset_id)
+            .map(|preset| preset.scene.clone())
+    }
+
+    pub fn transition_for_preset(&self, preset_id: &str) -> Option<(u32, SceneTransitionStyle)> {
+        self.presets
+            .iter()
+            .find(|preset| preset.preset_id == preset_id)
+            .map(|preset| (preset.transition_duration_ms, preset.transition_style))
+    }
+
+    pub fn recall_creative_snapshot(
+        &self,
+        snapshot_id: &str,
+    ) -> Option<StoredCreativeSnapshot> {
+        self.creative_snapshots
+            .iter()
+            .find(|snapshot| snapshot.snapshot_id == snapshot_id)
+            .cloned()
+    }
+
+    pub fn has_group(&self, group_id: &str) -> bool {
+        self.groups.iter().any(|group| group.group_id == group_id)
+    }
+
+    pub fn group_members_map(&self) -> BTreeMap<String, BTreeSet<String>> {
+        self.groups
+            .iter()
+            .map(|group| {
+                let members = group
+                    .members
+                    .iter()
+                    .map(|member| {
+                        format!(
+                            "{}:{}",
+                            member.node_id,
+                            panel_position_key(&member.panel_position)
+                        )
+                    })
+                    .collect();
+                (group.group_id.clone(), members)
+            })
+            .collect()
+    }
+
+    pub fn save_preset_from_scene(
+        &mut self,
+        preset_id: &str,
+        scene: &SceneRuntime,
+        transition_duration_ms: u32,
+        transition_style: SceneTransitionStyle,
+        overwrite: bool,
+    ) -> Result<(), HostCommandError> {
+        if preset_id.trim().is_empty() {
+            return Err(HostCommandError::new(
+                "invalid_preset_id",
+                "preset_id must not be empty",
+            ));
+        }
+
+        if let Some(existing) = self.presets.iter().find(|preset| preset.preset_id == preset_id) {
+            if !overwrite {
+                return Err(HostCommandError::new(
+                    "preset_exists",
+                    format!("preset '{preset_id}' already exists"),
+                ));
+            }
+
+            if existing.source == CatalogSource::BuiltIn {
+                // Overwriting a built-in preset becomes a runtime overlay with the same id.
+            }
+        }
+
+        let preset = StoredPreset {
+            preset_id: preset_id.to_string(),
+            scene: scene.clone(),
+            transition_duration_ms,
+            transition_style,
+            source: CatalogSource::RuntimeUser,
+            updated_at_unix_ms: Some(now_unix_ms()),
+        };
+        replace_or_append_by(&mut self.presets, preset, |left, right| {
+            left.preset_id == right.preset_id
+        });
+        Ok(())
+    }
+
+    pub fn save_creative_snapshot(
+        &mut self,
+        snapshot_id: &str,
+        label: Option<String>,
+        scene: &SceneRuntime,
+        transition_duration_ms: u32,
+        transition_style: SceneTransitionStyle,
+        overwrite: bool,
+    ) -> Result<(), HostCommandError> {
+        if snapshot_id.trim().is_empty() {
+            return Err(HostCommandError::new(
+                "invalid_snapshot_id",
+                "snapshot_id must not be empty",
+            ));
+        }
+
+        if self
+            .creative_snapshots
+            .iter()
+            .any(|snapshot| snapshot.snapshot_id == snapshot_id)
+            && !overwrite
+        {
+            return Err(HostCommandError::new(
+                "snapshot_exists",
+                format!("creative snapshot '{snapshot_id}' already exists"),
+            ));
+        }
+
+        let snapshot = StoredCreativeSnapshot {
+            snapshot_id: snapshot_id.to_string(),
+            label,
+            scene: scene.clone(),
+            transition_duration_ms,
+            transition_style,
+            saved_at_unix_ms: now_unix_ms(),
+            source_preset_id: scene.preset_id.clone(),
+        };
+        replace_or_append_by(&mut self.creative_snapshots, snapshot, |left, right| {
+            left.snapshot_id == right.snapshot_id
+        });
+        Ok(())
+    }
+
+    pub fn upsert_group(
+        &mut self,
+        group_id: &str,
+        tags: Vec<String>,
+        members: Vec<PanelTarget>,
+        overwrite: bool,
+    ) -> Result<(), HostCommandError> {
+        if group_id.trim().is_empty() {
+            return Err(HostCommandError::new(
+                "invalid_group_id",
+                "group_id must not be empty",
+            ));
+        }
+        if members.is_empty() {
+            return Err(HostCommandError::new(
+                "invalid_group_members",
+                "group must contain at least one panel target",
+            ));
+        }
+
+        if self.groups.iter().any(|group| group.group_id == group_id) && !overwrite {
+            return Err(HostCommandError::new(
+                "group_exists",
+                format!("group '{group_id}' already exists"),
+            ));
+        }
+
+        let group = StoredGroup {
+            group_id: group_id.to_string(),
+            tags,
+            members,
+            source: CatalogSource::RuntimeUser,
+            updated_at_unix_ms: Some(now_unix_ms()),
+        };
+        replace_or_append_by(&mut self.groups, group, |left, right| {
+            left.group_id == right.group_id
+        });
+        Ok(())
+    }
+
+    pub fn persisted_runtime(
+        &self,
+        active_scene: &SceneRuntime,
+        global: PersistedGlobalState,
+    ) -> PersistedRuntimeState {
+        PersistedRuntimeState {
+            active_scene: Some(active_scene.clone()),
+            global,
+            user_presets: self
+                .presets
+                .iter()
+                .filter(|preset| preset.source == CatalogSource::RuntimeUser)
+                .cloned()
+                .collect(),
+            user_groups: self
+                .groups
+                .iter()
+                .filter(|group| group.source == CatalogSource::RuntimeUser)
+                .cloned()
+                .collect(),
+            creative_snapshots: self.creative_snapshots.clone(),
+        }
+    }
+}
+
+fn panel_position_key(position: &PanelPosition) -> &'static str {
+    match position {
+        PanelPosition::Top => "top",
+        PanelPosition::Middle => "middle",
+        PanelPosition::Bottom => "bottom",
+    }
+}
+
+fn replace_or_append_by<T, F>(items: &mut Vec<T>, item: T, predicate: F)
+where
+    F: Fn(&T, &T) -> bool,
+{
+    if let Some(index) = items.iter().position(|existing| predicate(existing, &item)) {
+        items[index] = item;
+    } else {
+        items.push(item);
+    }
+}
+
+fn now_unix_ms() -> u64 {
+    SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .map(|duration| duration.as_millis() as u64)
+        .unwrap_or(0)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::time::{SystemTime, UNIX_EPOCH};
+
+    fn sample_project() -> ProjectConfig {
+        ProjectConfig::from_toml_str(include_str!("../../../config/project.example.toml"))
+            .expect("project config must parse")
+    }
+
+    #[test]
+    fn show_store_builds_runtime_catalog() {
+        let registry = PatternRegistry::new();
+        let store = ShowStore::from_project(&sample_project(), &registry);
+        let catalog = store.catalog(&registry);
+        assert!(catalog
+            .presets
+            .iter()
+            .any(|preset| preset.preset_id == "ocean_gradient"));
+        assert!(catalog.groups.iter().any(|group| group.group_id == "top_panels"));
+    }
+
+    #[test]
+    fn runtime_presets_and_snapshots_can_be_saved() {
+        let registry = PatternRegistry::new();
+        let mut store = ShowStore::from_project(&sample_project(), &registry);
+        let scene = registry.scene_for_pattern(
+            "gradient",
+            None,
+            Some("top_panels".to_string()),
+            77,
+            vec!["#112233".to_string(), "#445566".to_string()],
+            false,
+        );
+
+        store
+            .save_preset_from_scene(
+                "user_gradient",
+                &scene,
+                420,
+                SceneTransitionStyle::Crossfade,
+                false,
+            )
+            .expect("preset save should succeed");
+        store
+            .save_creative_snapshot(
+                "variant_a",
+                Some("Variant A".to_string()),
+                &scene,
+                240,
+                SceneTransitionStyle::Chase,
+                false,
+            )
+            .expect("snapshot save should succeed");
+
+        assert!(store.scene_from_preset_id("user_gradient").is_some());
+        assert!(store.recall_creative_snapshot("variant_a").is_some());
+    }
+
+    #[test]
+    fn runtime_state_storage_roundtrip_preserves_scene_and_library() {
+        let registry = PatternRegistry::new();
+        let mut store = ShowStore::from_project(&sample_project(), &registry);
+        let scene = registry.scene_for_pattern(
+            "noise",
+            None,
+            Some("bottom_panels".to_string()),
+            99,
+            vec!["#AA8844".to_string()],
+            false,
+        );
+        store
+            .save_preset_from_scene(
+                "roundtrip_noise",
+                &scene,
+                220,
+                SceneTransitionStyle::Chase,
+                false,
+            )
+            .expect("preset save should succeed");
+
+        let path = std::env::temp_dir().join(format!(
+            "infinity_vis_show_store_{}.json",
+            SystemTime::now()
+                .duration_since(UNIX_EPOCH)
+                .expect("system time")
+                .as_millis()
+        ));
+        let storage = RuntimeStateStorage::new(&path);
+        let runtime = store.persisted_runtime(
+            &scene,
+            PersistedGlobalState {
+                blackout: false,
+                master_brightness: 0.42,
+                transition_duration_ms: 220,
+                transition_style: SceneTransitionStyle::Chase,
+            },
+        );
+        storage.save(&runtime).expect("save should work");
+        let loaded = storage.load().expect("load should work");
+
+        assert_eq!(loaded.active_scene, Some(scene));
+        assert!(loaded
+            .user_presets
+            .iter()
+            .any(|preset| preset.preset_id == "roundtrip_noise"));
+
+        let _ = std::fs::remove_file(path);
+    }
+}

crates/infinity_host/src/simulation.rs

@@ -1,19 +1,23 @@
 use crate::{
     control::{
-        EngineSnapshot, GlobalControlSnapshot, HostApiPort, HostCommand, HostSnapshot,
-        HOST_API_VERSION, NodeConnectionState, NodeSnapshot, PanelSnapshot, PanelTarget,
-        PreviewPanelSnapshot, PreviewSource, StatusEvent, SystemSnapshot,
+        CatalogSnapshot, CommandOutcome, EngineSnapshot, GlobalControlSnapshot, HostApiPort,
+        HostCommand, HostCommandError, HostSnapshot, HOST_API_VERSION, NodeConnectionState,
+        NodeSnapshot, PanelSnapshot, PanelTarget, PreviewPanelSnapshot, PreviewSource,
+        SceneTransitionStyle, StatusEvent, StatusEventKind, SystemSnapshot,
     },
     runtime::TickSchedule,
     scene::{
-        apply_group_gate, blackout_preview, blend_previews, build_group_members,
-        panel_membership_key, panel_test_preview, transition_style_from_duration, PatternRegistry,
-        RenderedPreview, SceneRuntime, TransitionRuntime,
+        apply_group_gate, blackout_preview, blend_previews, panel_membership_key,
+        panel_test_preview, PatternRegistry, RenderedPreview, SceneRuntime, TransitionRuntime,
+    },
+    show_store::{
+        PersistedGlobalState, RuntimeStateStorage, ShowStore, ShowStoreError,
     },
 };
 use infinity_config::{PanelPosition, ProjectConfig};
 use std::{
     collections::BTreeMap,
+    path::PathBuf,
     sync::{Arc, Mutex},
     thread,
     time::{Duration, Instant},
@@ -29,9 +33,10 @@ pub struct SimulationHostService {
 
 #[derive(Debug)]
 struct SimulationState {
-    project: ProjectConfig,
     registry: PatternRegistry,
     group_members: BTreeMap<String, std::collections::BTreeSet<String>>,
+    show_store: ShowStore,
+    runtime_storage: Option<RuntimeStateStorage>,
     started_at: Instant,
     next_seed: u64,
     tick_count: u64,
@@ -45,9 +50,7 @@ struct SimulationState {
 
 impl SimulationHostService {
     pub fn new(project: ProjectConfig) -> Self {
-        Self {
-            inner: Arc::new(Mutex::new(SimulationState::new(project))),
-        }
+        Self::try_new(project).expect("memory-only simulation host service must initialize")
     }
 
     pub fn spawn_shared(project: ProjectConfig) -> Arc<Self> {
@@ -56,6 +59,33 @@ impl SimulationHostService {
         service
     }
 
+    pub fn try_new(project: ProjectConfig) -> Result<Self, ShowStoreError> {
+        Ok(Self {
+            inner: Arc::new(Mutex::new(SimulationState::try_new(project, None)?)),
+        })
+    }
+
+    pub fn try_new_with_persistence(
+        project: ProjectConfig,
+        runtime_state_path: impl Into<PathBuf>,
+    ) -> Result<Self, ShowStoreError> {
+        Ok(Self {
+            inner: Arc::new(Mutex::new(SimulationState::try_new(
+                project,
+                Some(RuntimeStateStorage::new(runtime_state_path)),
+            )?)),
+        })
+    }
+
+    pub fn try_spawn_shared_with_persistence(
+        project: ProjectConfig,
+        runtime_state_path: impl Into<PathBuf>,
+    ) -> Result<Arc<Self>, ShowStoreError> {
+        let service = Arc::new(Self::try_new_with_persistence(project, runtime_state_path)?);
+        Self::spawn_simulation_loop(Arc::clone(&service));
+        Ok(service)
+    }
+
     fn spawn_simulation_loop(service: Arc<Self>) {
         thread::spawn(move || loop {
             thread::sleep(Duration::from_millis(80));
@@ -74,25 +104,38 @@ impl HostApiPort for SimulationHostService {
             .unwrap_or_else(|_| unavailable_snapshot())
     }
 
-    fn send_command(&self, command: HostCommand) {
+    fn send_command(&self, command: HostCommand) -> Result<CommandOutcome, HostCommandError> {
         if let Ok(mut state) = self.inner.lock() {
-            state.apply_command(command);
+            state.apply_command(command)
+        } else {
+            Err(HostCommandError::new(
+                "service_unavailable",
+                "simulation state lock was unavailable",
+            ))
         }
     }
 }
 
 impl SimulationState {
-    fn new(project: ProjectConfig) -> Self {
+    fn try_new(
+        project: ProjectConfig,
+        runtime_storage: Option<RuntimeStateStorage>,
+    ) -> Result<Self, ShowStoreError> {
         let registry = PatternRegistry::new();
-        let group_members = build_group_members(&project);
+        let mut show_store = ShowStore::from_project(&project, &registry);
+        let persisted_runtime = if let Some(storage) = &runtime_storage {
+            storage.load()?
+        } else {
+            Default::default()
+        };
+        let restored_scene = persisted_runtime.active_scene.clone();
+        let restored_global = persisted_runtime.global.clone();
+        show_store.apply_persisted(persisted_runtime);
+        let group_members = show_store.group_members_map();
         let schedule = TickSchedule::default();
-        let current_scene = registry.initial_scene(&project);
-        let catalog = registry.catalog(&project);
-        let available_patterns = catalog
-            .patterns
-            .iter()
-            .map(|pattern| pattern.pattern_id.clone())
-            .collect::<Vec<_>>();
+        let current_scene = restored_scene.unwrap_or_else(|| show_store.initial_scene(&registry));
+        let catalog = show_store.catalog(&registry);
+        let available_patterns = show_store.available_patterns(&registry);
         let nodes = project
             .topology
             .nodes
@@ -131,10 +174,12 @@ impl SimulationState {
             })
             .collect::<Vec<_>>();
 
+        let selected_pattern = current_scene.pattern_id.clone();
         let mut state = Self {
-            project: project.clone(),
             registry,
             group_members,
+            show_store,
+            runtime_storage,
             started_at: Instant::now(),
             next_seed: 100,
             tick_count: 0,
@@ -153,11 +198,12 @@ impl SimulationState {
                     topology_label: "6 nodes / 18 outputs / 106 LEDs".to_string(),
                 },
                 global: GlobalControlSnapshot {
-                    blackout: false,
-                    master_brightness: 0.20,
-                    selected_pattern: "solid_color".to_string(),
+                    blackout: restored_global.blackout,
+                    master_brightness: restored_global.master_brightness,
+                    selected_pattern,
                     selected_group: None,
-                    transition_duration_ms: 150,
+                    transition_duration_ms: restored_global.transition_duration_ms,
+                    transition_style: restored_global.transition_style,
                 },
                 engine: EngineSnapshot {
                     logic_hz: schedule.logic_hz,
@@ -188,9 +234,16 @@ impl SimulationState {
         state.snapshot.global.selected_pattern = state.current_scene.pattern_id.clone();
         state.snapshot.global.selected_group = state.current_scene.target_group.clone();
         state.snapshot.active_scene = state.registry.active_scene_snapshot(&state.current_scene);
-        state.push_event("simulation host service started".to_string());
+        state.push_event(StatusEventKind::Info, None, "simulation host service started".to_string());
+        if state.runtime_storage.is_some() {
+            state.push_event(
+                StatusEventKind::Info,
+                Some("runtime_state_restored".to_string()),
+                "runtime state persistence enabled".to_string(),
+            );
+        }
         state.simulate_tick();
-        state
+        Ok(state)
     }
 
     fn simulate_tick(&mut self) {
@@ -218,22 +271,29 @@ impl SimulationState {
         self.snapshot.preview.panels = self.render_preview_panels(elapsed_ms);
     }
 
-    fn apply_command(&mut self, command: HostCommand) {
-        match command {
+    fn apply_command(&mut self, command: HostCommand) -> Result<CommandOutcome, HostCommandError> {
+        let mut should_persist = false;
+        let summary = match command {
             HostCommand::SetBlackout(enabled) => {
                 self.snapshot.global.blackout = enabled;
-                self.push_event(if enabled {
+                should_persist = true;
+                let summary = if enabled {
                     "global blackout enabled".to_string()
                 } else {
                     "global blackout released".to_string()
-                });
+                };
+                self.push_event(StatusEventKind::Info, None, summary.clone());
+                summary
             }
             HostCommand::SetMasterBrightness(value) => {
                 self.snapshot.global.master_brightness = value.clamp(0.0, 1.0);
-                self.push_event(format!(
+                should_persist = true;
+                let summary = format!(
                     "master brightness set to {:.0}%",
                     self.snapshot.global.master_brightness * 100.0
-                ));
+                );
+                self.push_event(StatusEventKind::Info, None, summary.clone());
+                summary
             }
             HostCommand::SelectPattern(pattern_id) => {
                 let mut new_scene = self.registry.scene_for_pattern(
@@ -255,55 +315,95 @@ impl SimulationState {
                 }
 
                 let duration_ms = self.snapshot.global.transition_duration_ms;
+                let style = self.snapshot.global.transition_style;
+                should_persist = true;
                 self.start_scene_transition(
                     new_scene,
                     duration_ms,
-                    transition_style_from_duration(duration_ms),
+                    style,
                     format!("pattern selected: {pattern_id}"),
                 );
+                format!("pattern selected: {pattern_id}")
             }
             HostCommand::RecallPreset { preset_id } => {
-                if let Some(scene) = self.registry.scene_from_preset_id(&self.project, &preset_id) {
-                    let duration_ms = self
-                        .project
-                        .presets
-                        .iter()
-                        .find(|preset| preset.preset_id == preset_id)
-                        .map(|preset| preset.transition_ms)
-                        .unwrap_or(self.snapshot.global.transition_duration_ms);
+                let Some(scene) = self.show_store.scene_from_preset_id(&preset_id) else {
+                    let error = HostCommandError::new(
+                        "unknown_preset",
+                        format!("preset '{preset_id}' does not exist"),
+                    );
+                    self.push_event(
+                        StatusEventKind::Warning,
+                        Some(error.code.clone()),
+                        error.message.clone(),
+                    );
+                    return Err(error);
+                };
+                let (duration_ms, style) = self
+                    .show_store
+                    .transition_for_preset(&preset_id)
+                    .unwrap_or((
+                        self.snapshot.global.transition_duration_ms,
+                        self.snapshot.global.transition_style,
+                    ));
                 self.snapshot.global.transition_duration_ms = duration_ms;
+                self.snapshot.global.transition_style = style;
+                should_persist = true;
                 self.start_scene_transition(
                     scene,
                     duration_ms,
-                        self.registry
-                            .transition_style_for_preset(&self.project, &preset_id),
+                    style,
                     format!("preset recalled: {preset_id}"),
                 );
-                } else {
-                    self.push_event(format!("ignored unknown preset request: {preset_id}"));
-                }
+                format!("preset recalled: {preset_id}")
             }
             HostCommand::SelectGroup { group_id } => {
+                if let Some(group_id_ref) = &group_id {
+                    if !self.show_store.has_group(group_id_ref) {
+                        let error = HostCommandError::new(
+                            "unknown_group",
+                            format!("group '{group_id_ref}' does not exist"),
+                        );
+                        self.push_event(
+                            StatusEventKind::Warning,
+                            Some(error.code.clone()),
+                            error.message.clone(),
+                        );
+                        return Err(error);
+                    }
+                }
                 self.current_scene.target_group = group_id.clone();
                 self.snapshot.global.selected_group = group_id.clone();
                 self.current_scene.preset_id = None;
-                self.push_event(format!(
+                should_persist = true;
+                let summary = format!(
                     "target group set to {}",
                     group_id.as_deref().unwrap_or("all_panels")
-                ));
+                );
+                self.push_event(StatusEventKind::Info, None, summary.clone());
+                summary
             }
             HostCommand::SetSceneParameter { key, value } => {
                 self.registry
                     .set_scene_parameter(&mut self.current_scene, &key, value.clone());
                 self.current_scene.preset_id = None;
-                self.push_event(format!("scene parameter updated: {key} = {value:?}"));
+                should_persist = true;
+                let summary = format!("scene parameter updated: {key} = {value:?}");
+                self.push_event(StatusEventKind::Info, None, summary.clone());
+                summary
             }
             HostCommand::SetTransitionDurationMs(duration_ms) => {
                 self.snapshot.global.transition_duration_ms = duration_ms;
-                self.push_event(format!(
-                    "default transition duration set to {} ms",
-                    duration_ms
-                ));
+                should_persist = true;
+                let summary = format!("default transition duration set to {} ms", duration_ms);
+                self.push_event(StatusEventKind::Info, None, summary.clone());
+                summary
+            }
+            HostCommand::SetTransitionStyle(style) => {
+                self.snapshot.global.transition_style = style;
+                should_persist = true;
+                let summary = format!("default transition style set to {}", style.label());
+                self.push_event(StatusEventKind::Info, None, summary.clone());
+                summary
             }
             HostCommand::TriggerPanelTest { target, pattern } => {
                 let now = self.elapsed_millis();
@@ -329,18 +429,114 @@ impl SimulationState {
                     );
                 }
 
-                self.push_event(message);
+                self.push_event(StatusEventKind::Info, None, message.clone());
+                message
             }
+            HostCommand::SavePreset {
+                preset_id,
+                overwrite,
+            } => {
+                self.show_store.save_preset_from_scene(
+                    &preset_id,
+                    &self.current_scene,
+                    self.snapshot.global.transition_duration_ms,
+                    self.snapshot.global.transition_style,
+                    overwrite,
+                )?;
+                self.rebuild_catalog();
+                self.group_members = self.show_store.group_members_map();
+                should_persist = true;
+                let summary = if overwrite {
+                    format!("preset overwritten: {preset_id}")
+                } else {
+                    format!("preset saved: {preset_id}")
+                };
+                self.push_event(StatusEventKind::Info, None, summary.clone());
+                summary
             }
+            HostCommand::SaveCreativeSnapshot {
+                snapshot_id,
+                label,
+                overwrite,
+            } => {
+                self.show_store.save_creative_snapshot(
+                    &snapshot_id,
+                    label.clone(),
+                    &self.current_scene,
+                    self.snapshot.global.transition_duration_ms,
+                    self.snapshot.global.transition_style,
+                    overwrite,
+                )?;
+                self.rebuild_catalog();
+                should_persist = true;
+                let summary = if overwrite {
+                    format!("creative snapshot overwritten: {snapshot_id}")
+                } else {
+                    format!("creative snapshot saved: {snapshot_id}")
+                };
+                self.push_event(StatusEventKind::Info, None, summary.clone());
+                summary
+            }
+            HostCommand::RecallCreativeSnapshot { snapshot_id } => {
+                let Some(snapshot) = self.show_store.recall_creative_snapshot(&snapshot_id) else {
+                    let error = HostCommandError::new(
+                        "unknown_creative_snapshot",
+                        format!("creative snapshot '{snapshot_id}' does not exist"),
+                    );
+                    self.push_event(
+                        StatusEventKind::Warning,
+                        Some(error.code.clone()),
+                        error.message.clone(),
+                    );
+                    return Err(error);
+                };
+                self.snapshot.global.transition_duration_ms = snapshot.transition_duration_ms;
+                self.snapshot.global.transition_style = snapshot.transition_style;
+                should_persist = true;
+                self.start_scene_transition(
+                    snapshot.scene,
+                    snapshot.transition_duration_ms,
+                    snapshot.transition_style,
+                    format!("creative snapshot recalled: {snapshot_id}"),
+                );
+                format!("creative snapshot recalled: {snapshot_id}")
+            }
+            HostCommand::UpsertGroup {
+                group_id,
+                tags,
+                members,
+                overwrite,
+            } => {
+                self.show_store
+                    .upsert_group(&group_id, tags, members, overwrite)?;
+                self.group_members = self.show_store.group_members_map();
+                self.rebuild_catalog();
+                should_persist = true;
+                let summary = if overwrite {
+                    format!("group updated: {group_id}")
+                } else {
+                    format!("group saved: {group_id}")
+                };
+                self.push_event(StatusEventKind::Info, None, summary.clone());
+                summary
+            }
+        };
 
         self.simulate_tick();
+        if should_persist {
+            self.persist_runtime_state()?;
+        }
+        Ok(CommandOutcome {
+            generated_at_millis: self.snapshot.generated_at_millis,
+            summary,
+        })
     }
 
     fn start_scene_transition(
         &mut self,
         new_scene: SceneRuntime,
         duration_ms: u32,
-        style: crate::control::SceneTransitionStyle,
+        style: SceneTransitionStyle,
         event_message: String,
     ) {
         let previous_scene = self.current_scene.clone();
@@ -355,7 +551,7 @@ impl SimulationState {
                 from_scene: previous_scene,
             })
         };
-        self.push_event(event_message);
+        self.push_event(StatusEventKind::Info, None, event_message);
     }
 
     fn resolve_transition_if_complete(&mut self) {
@@ -367,7 +563,7 @@ impl SimulationState {
 
         if finished {
             self.active_transition = None;
-            self.push_event(format!(
+            self.push_event(StatusEventKind::Info, None, format!(
                 "transition completed to {}",
                 self.current_scene.pattern_id
             ));
@@ -403,7 +599,11 @@ impl SimulationState {
         }
 
         for message in transition_messages {
-            self.push_event(message);
+            self.push_event(
+                StatusEventKind::Warning,
+                Some("node_connection_state".to_string()),
+                message,
+            );
         }
     }
 
@@ -501,11 +701,58 @@ impl SimulationState {
         (scale_preview(preview, self.snapshot.global.master_brightness), source)
     }
 
-    fn push_event(&mut self, message: String) {
+    fn rebuild_catalog(&mut self) {
+        self.snapshot.catalog = self.show_store.catalog(&self.registry);
+    }
+
+    fn persisted_global_state(&self) -> PersistedGlobalState {
+        PersistedGlobalState {
+            blackout: self.snapshot.global.blackout,
+            master_brightness: self.snapshot.global.master_brightness,
+            transition_duration_ms: self.snapshot.global.transition_duration_ms,
+            transition_style: self.snapshot.global.transition_style,
+        }
+    }
+
+    fn persist_runtime_state(&mut self) -> Result<(), HostCommandError> {
+        let Some(storage) = &self.runtime_storage else {
+            return Ok(());
+        };
+        let storage_path = storage.path().to_path_buf();
+
+        let runtime_state = self
+            .show_store
+            .persisted_runtime(&self.current_scene, self.persisted_global_state());
+        if let Err(error) = storage.save(&runtime_state) {
+            let command_error = HostCommandError::new(
+                "persist_failed",
+                format!(
+                    "runtime state could not be saved to {}: {error}",
+                    storage_path.display()
+                ),
+            );
+            self.push_event(
+                StatusEventKind::Error,
+                Some(command_error.code.clone()),
+                command_error.message.clone(),
+            );
+            return Err(command_error);
+        }
+        Ok(())
+    }
+
+    fn push_event(
+        &mut self,
+        kind: StatusEventKind,
+        code: Option<String>,
+        message: String,
+    ) {
         self.snapshot.recent_events.insert(
             0,
             StatusEvent {
                 at_millis: self.elapsed_millis(),
+                kind,
+                code,
                 message,
             },
         );
@@ -533,6 +780,7 @@ fn unavailable_snapshot() -> HostSnapshot {
             selected_pattern: "unavailable".to_string(),
             selected_group: None,
             transition_duration_ms: 0,
+            transition_style: SceneTransitionStyle::Snap,
         },
         engine: EngineSnapshot {
             logic_hz: 0,
@@ -543,10 +791,11 @@ fn unavailable_snapshot() -> HostSnapshot {
             dropped_frames: 0,
             active_transition: None,
         },
-        catalog: crate::control::CatalogSnapshot {
+        catalog: CatalogSnapshot {
             patterns: Vec::new(),
             presets: Vec::new(),
             groups: Vec::new(),
+            creative_snapshots: Vec::new(),
         },
         active_scene: crate::control::ActiveSceneSnapshot {
             preset_id: None,
@@ -563,6 +812,8 @@ fn unavailable_snapshot() -> HostSnapshot {
         panels: Vec::new(),
         recent_events: vec![StatusEvent {
             at_millis: 0,
+            kind: StatusEventKind::Error,
+            code: Some("service_unavailable".to_string()),
             message: "simulation service lock was unavailable".to_string(),
         }],
     }
@@ -668,13 +919,13 @@ mod tests {
     #[test]
     fn commands_update_scene_and_group() {
         let service = SimulationHostService::new(sample_project());
-        service.send_command(HostCommand::SelectGroup {
+        let _ = service.send_command(HostCommand::SelectGroup {
             group_id: Some("top_panels".to_string()),
         });
-        service.send_command(HostCommand::RecallPreset {
+        let _ = service.send_command(HostCommand::RecallPreset {
             preset_id: "mapping_walk_test".to_string(),
         });
-        service.send_command(HostCommand::SetSceneParameter {
+        let _ = service.send_command(HostCommand::SetSceneParameter {
             key: "speed".to_string(),
             value: SceneParameterValue::Scalar(2.0),
         });
@@ -688,4 +939,22 @@ mod tests {
             .iter()
             .any(|parameter| parameter.key == "speed"));
     }
+
+    #[test]
+    fn unknown_group_returns_typed_error_and_warning_event() {
+        let service = SimulationHostService::new(sample_project());
+        let error = service
+            .send_command(HostCommand::SelectGroup {
+                group_id: Some("does_not_exist".to_string()),
+            })
+            .expect_err("unknown group should fail");
+
+        let snapshot = service.snapshot();
+        assert_eq!(error.code, "unknown_group");
+        assert!(snapshot
+            .recent_events
+            .iter()
+            .any(|event| event.kind == StatusEventKind::Warning
+                && event.code.as_deref() == Some("unknown_group")));
+    }
 }

crates/infinity_host_api/src/dto.rs

@@ -1,7 +1,8 @@
 use infinity_config::{ColorOrder, LedDirection, PanelPosition, ValidationState};
 use infinity_host::{
-    HostCommand, HostSnapshot, NodeConnectionState, PreviewSource, SceneParameterKind,
-    SceneParameterValue, SceneTransitionStyle, TestPatternKind,
+    CatalogSource, HostCommand, HostSnapshot, NodeConnectionState, PreviewSource,
+    SceneParameterKind, SceneParameterValue, SceneTransitionStyle, StatusEventKind,
+    TestPatternKind,
 };
 use serde::{Deserialize, Serialize};
 
@@ -15,12 +16,27 @@ pub struct ApiSnapshotResponse {
     pub preview: ApiPreviewSnapshot,
 }
 
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+pub struct ApiStateResponse {
+    pub api_version: &'static str,
+    pub generated_at_millis: u64,
+    pub state: ApiStateSnapshot,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+pub struct ApiPreviewResponse {
+    pub api_version: &'static str,
+    pub generated_at_millis: u64,
+    pub preview: ApiPreviewSnapshot,
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
 pub struct ApiCatalogResponse {
     pub api_version: &'static str,
     pub patterns: Vec<ApiPatternCatalogEntry>,
     pub presets: Vec<ApiPresetSummary>,
     pub groups: Vec<ApiGroupSummary>,
+    pub creative_snapshots: Vec<ApiCreativeSnapshotSummary>,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
@@ -48,6 +64,7 @@ pub struct ApiCommandResponse {
     pub accepted: bool,
     pub request_id: Option<String>,
     pub generated_at_millis: u64,
+    pub command_type: String,
     pub summary: String,
 }
 
@@ -98,6 +115,7 @@ pub enum ApiStreamMessage {
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
 pub struct ApiEventNotice {
     pub kind: ApiEventKind,
+    pub code: Option<String>,
     pub message: String,
 }
 
@@ -105,6 +123,8 @@ pub struct ApiEventNotice {
 #[serde(rename_all = "snake_case")]
 pub enum ApiEventKind {
     Info,
+    Warning,
+    Error,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
@@ -121,6 +141,7 @@ pub struct ApiGlobalState {
     pub selected_pattern: String,
     pub selected_group: Option<String>,
     pub transition_duration_ms: u32,
+    pub transition_style: ApiTransitionStyle,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
@@ -198,6 +219,8 @@ pub struct ApiPresetSummary {
     pub pattern_id: String,
     pub target_group: Option<String>,
     pub transition_duration_ms: u32,
+    pub transition_style: ApiTransitionStyle,
+    pub source: ApiCatalogSource,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
@@ -205,6 +228,18 @@ pub struct ApiGroupSummary {
     pub group_id: String,
     pub member_count: usize,
     pub tags: Vec<String>,
+    pub source: ApiCatalogSource,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+pub struct ApiCreativeSnapshotSummary {
+    pub snapshot_id: String,
+    pub label: Option<String>,
+    pub pattern_id: String,
+    pub target_group: Option<String>,
+    pub transition_duration_ms: u32,
+    pub transition_style: ApiTransitionStyle,
+    pub saved_at_unix_ms: u64,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
@@ -277,6 +312,13 @@ pub enum ApiParameterKind {
     Text,
 }
 
+#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
+#[serde(rename_all = "snake_case")]
+pub enum ApiCatalogSource {
+    BuiltIn,
+    RuntimeUser,
+}
+
 #[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
 #[serde(rename_all = "snake_case")]
 pub enum ApiLedDirection {
@@ -336,11 +378,38 @@ pub enum ApiCommand {
     SetTransitionDurationMs {
         duration_ms: u32,
     },
+    SetTransitionStyle {
+        style: ApiTransitionStyle,
+    },
     TriggerPanelTest {
         node_id: String,
         panel_position: ApiPanelPosition,
         pattern: ApiTestPattern,
     },
+    SavePreset {
+        preset_id: String,
+        overwrite: bool,
+    },
+    SaveCreativeSnapshot {
+        snapshot_id: String,
+        label: Option<String>,
+        overwrite: bool,
+    },
+    RecallCreativeSnapshot {
+        snapshot_id: String,
+    },
+    UpsertGroup {
+        group_id: String,
+        tags: Vec<String>,
+        members: Vec<ApiPanelRef>,
+        overwrite: bool,
+    },
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
+pub struct ApiPanelRef {
+    pub node_id: String,
+    pub panel_position: ApiPanelPosition,
 }
 
 #[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
@@ -362,6 +431,26 @@ impl ApiSnapshotResponse {
     }
 }
 
+impl ApiStateResponse {
+    pub fn from_snapshot(snapshot: &HostSnapshot) -> Self {
+        Self {
+            api_version: API_VERSION,
+            generated_at_millis: snapshot.generated_at_millis,
+            state: ApiStateSnapshot::from_snapshot(snapshot),
+        }
+    }
+}
+
+impl ApiPreviewResponse {
+    pub fn from_snapshot(snapshot: &HostSnapshot) -> Self {
+        Self {
+            api_version: API_VERSION,
+            generated_at_millis: snapshot.generated_at_millis,
+            preview: ApiPreviewSnapshot::from_snapshot(snapshot),
+        }
+    }
+}
+
 impl ApiCatalogResponse {
     pub fn from_snapshot(snapshot: &HostSnapshot) -> Self {
         Self {
@@ -398,6 +487,8 @@ impl ApiCatalogResponse {
                     pattern_id: preset.pattern_id.clone(),
                     target_group: preset.target_group.clone(),
                     transition_duration_ms: preset.transition_duration_ms,
+                    transition_style: map_transition_style(preset.transition_style),
+                    source: map_catalog_source(preset.source),
                 })
                 .collect(),
             groups: snapshot
@@ -408,6 +499,21 @@ impl ApiCatalogResponse {
                     group_id: group.group_id.clone(),
                     member_count: group.member_count,
                     tags: group.tags.clone(),
+                    source: map_catalog_source(group.source),
+                })
+                .collect(),
+            creative_snapshots: snapshot
+                .catalog
+                .creative_snapshots
+                .iter()
+                .map(|snapshot| ApiCreativeSnapshotSummary {
+                    snapshot_id: snapshot.snapshot_id.clone(),
+                    label: snapshot.label.clone(),
+                    pattern_id: snapshot.pattern_id.clone(),
+                    target_group: snapshot.target_group.clone(),
+                    transition_duration_ms: snapshot.transition_duration_ms,
+                    transition_style: map_transition_style(snapshot.transition_style),
+                    saved_at_unix_ms: snapshot.saved_at_unix_ms,
                 })
                 .collect(),
         }
@@ -446,6 +552,7 @@ impl ApiStateSnapshot {
                 selected_pattern: snapshot.global.selected_pattern.clone(),
                 selected_group: snapshot.global.selected_group.clone(),
                 transition_duration_ms: snapshot.global.transition_duration_ms,
+                transition_style: map_transition_style(snapshot.global.transition_style),
             },
             engine: ApiEngineState {
                 logic_hz: snapshot.engine.logic_hz,
@@ -565,6 +672,9 @@ impl ApiCommandRequest {
             ApiCommand::SetTransitionDurationMs { duration_ms } => {
                 Ok(HostCommand::SetTransitionDurationMs(duration_ms))
             }
+            ApiCommand::SetTransitionStyle { style } => {
+                Ok(HostCommand::SetTransitionStyle(map_command_transition_style(style)))
+            }
             ApiCommand::TriggerPanelTest {
                 node_id,
                 panel_position,
@@ -578,6 +688,42 @@ impl ApiCommandRequest {
                     ApiTestPattern::WalkingPixel106 => TestPatternKind::WalkingPixel106,
                 },
             }),
+            ApiCommand::SavePreset {
+                preset_id,
+                overwrite,
+            } => Ok(HostCommand::SavePreset {
+                preset_id,
+                overwrite,
+            }),
+            ApiCommand::SaveCreativeSnapshot {
+                snapshot_id,
+                label,
+                overwrite,
+            } => Ok(HostCommand::SaveCreativeSnapshot {
+                snapshot_id,
+                label,
+                overwrite,
+            }),
+            ApiCommand::RecallCreativeSnapshot { snapshot_id } => {
+                Ok(HostCommand::RecallCreativeSnapshot { snapshot_id })
+            }
+            ApiCommand::UpsertGroup {
+                group_id,
+                tags,
+                members,
+                overwrite,
+            } => Ok(HostCommand::UpsertGroup {
+                group_id,
+                tags,
+                members: members
+                    .into_iter()
+                    .map(|member| infinity_host::PanelTarget {
+                        node_id: member.node_id,
+                        panel_position: map_command_panel_position(member.panel_position),
+                    })
+                    .collect(),
+                overwrite,
+            }),
         }
     }
 
@@ -653,6 +799,29 @@ fn map_transition_style(style: SceneTransitionStyle) -> ApiTransitionStyle {
     }
 }
 
+fn map_command_transition_style(style: ApiTransitionStyle) -> SceneTransitionStyle {
+    match style {
+        ApiTransitionStyle::Snap => SceneTransitionStyle::Snap,
+        ApiTransitionStyle::Crossfade => SceneTransitionStyle::Crossfade,
+        ApiTransitionStyle::Chase => SceneTransitionStyle::Chase,
+    }
+}
+
+fn map_catalog_source(source: CatalogSource) -> ApiCatalogSource {
+    match source {
+        CatalogSource::BuiltIn => ApiCatalogSource::BuiltIn,
+        CatalogSource::RuntimeUser => ApiCatalogSource::RuntimeUser,
+    }
+}
+
+fn map_event_kind(kind: StatusEventKind) -> ApiEventKind {
+    match kind {
+        StatusEventKind::Info => ApiEventKind::Info,
+        StatusEventKind::Warning => ApiEventKind::Warning,
+        StatusEventKind::Error => ApiEventKind::Error,
+    }
+}
+
 fn map_parameter_kind(kind: SceneParameterKind) -> ApiParameterKind {
     match kind {
         SceneParameterKind::Scalar => ApiParameterKind::Scalar,
@@ -678,6 +847,24 @@ fn map_command_parameter_value(value: ApiParameterValue) -> SceneParameterValue
 }
 
 impl ApiCommand {
+    pub fn kind_label(&self) -> &'static str {
+        match self {
+            Self::SetBlackout { .. } => "set_blackout",
+            Self::SetMasterBrightness { .. } => "set_master_brightness",
+            Self::SelectPattern { .. } => "select_pattern",
+            Self::RecallPreset { .. } => "recall_preset",
+            Self::SelectGroup { .. } => "select_group",
+            Self::SetSceneParameter { .. } => "set_scene_parameter",
+            Self::SetTransitionDurationMs { .. } => "set_transition_duration_ms",
+            Self::SetTransitionStyle { .. } => "set_transition_style",
+            Self::TriggerPanelTest { .. } => "trigger_panel_test",
+            Self::SavePreset { .. } => "save_preset",
+            Self::SaveCreativeSnapshot { .. } => "save_creative_snapshot",
+            Self::RecallCreativeSnapshot { .. } => "recall_creative_snapshot",
+            Self::UpsertGroup { .. } => "upsert_group",
+        }
+    }
+
     pub fn summary(&self) -> String {
         match self {
             Self::SetBlackout { enabled } => {
@@ -700,6 +887,9 @@ impl ApiCommand {
             Self::SetTransitionDurationMs { duration_ms } => {
                 format!("transition duration set to {duration_ms} ms")
             }
+            Self::SetTransitionStyle { style } => {
+                format!("transition style set to {}", style.label())
+            }
             Self::TriggerPanelTest {
                 node_id,
                 panel_position,
@@ -710,6 +900,38 @@ impl ApiCommand {
                 node_id,
                 panel_position.label()
             ),
+            Self::SavePreset { preset_id, overwrite } => {
+                if *overwrite {
+                    format!("preset overwritten: {preset_id}")
+                } else {
+                    format!("preset saved: {preset_id}")
+                }
+            }
+            Self::SaveCreativeSnapshot {
+                snapshot_id,
+                overwrite,
+                ..
+            } => {
+                if *overwrite {
+                    format!("creative snapshot overwritten: {snapshot_id}")
+                } else {
+                    format!("creative snapshot saved: {snapshot_id}")
+                }
+            }
+            Self::RecallCreativeSnapshot { snapshot_id } => {
+                format!("creative snapshot recalled: {snapshot_id}")
+            }
+            Self::UpsertGroup {
+                group_id,
+                overwrite,
+                ..
+            } => {
+                if *overwrite {
+                    format!("group updated: {group_id}")
+                } else {
+                    format!("group saved: {group_id}")
+                }
+            }
         }
     }
 }
@@ -724,6 +946,16 @@ impl ApiPanelPosition {
     }
 }
 
+impl ApiTransitionStyle {
+    pub fn label(self) -> &'static str {
+        match self {
+            Self::Snap => "snap",
+            Self::Crossfade => "crossfade",
+            Self::Chase => "chase",
+        }
+    }
+}
+
 impl ApiTestPattern {
     pub fn label(self) -> &'static str {
         match self {
@@ -743,3 +975,13 @@ impl ApiErrorResponse {
         }
     }
 }
+
+impl From<infinity_host::StatusEvent> for ApiEventNotice {
+    fn from(event: infinity_host::StatusEvent) -> Self {
+        Self {
+            kind: map_event_kind(event.kind),
+            code: event.code,
+            message: event.message,
+        }
+    }
+}

crates/infinity_host_api/src/main.rs

@@ -11,16 +11,23 @@ struct Cli {
     config: PathBuf,
     #[arg(long, default_value = "127.0.0.1:9001")]
     bind: String,
+    #[arg(long, default_value = "data/runtime_state.json")]
+    runtime_state: PathBuf,
 }
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     let cli = Cli::parse();
     let project = load_project(&cli.config)?;
-    let service: Arc<dyn HostApiPort> = SimulationHostService::spawn_shared(project);
+    let service: Arc<dyn HostApiPort> =
+        SimulationHostService::try_spawn_shared_with_persistence(project, &cli.runtime_state)?;
     let server = HostApiServer::bind(&cli.bind, service)?;
 
     println!("Infinity Vis host API listening on http://{}", server.local_addr());
     println!("Web UI available at http://{}/", server.local_addr());
+    println!(
+        "Runtime state persistence: {}",
+        cli.runtime_state.display()
+    );
 
     loop {
         thread::sleep(Duration::from_secs(60));

crates/infinity_host_api/src/server.rs

@@ -1,7 +1,7 @@
 use crate::dto::{
-    ApiCatalogResponse, ApiCommandRequest, ApiCommandResponse, ApiErrorResponse, ApiEventKind,
-    ApiEventNotice, ApiGroupListResponse, ApiPresetListResponse, ApiSnapshotResponse,
-    ApiStateSnapshot, ApiStreamEnvelope, ApiStreamMessage, API_VERSION,
+    ApiCatalogResponse, ApiCommandRequest, ApiCommandResponse, ApiErrorResponse,
+    ApiGroupListResponse, ApiPresetListResponse, ApiPreviewResponse, ApiSnapshotResponse,
+    ApiStateResponse, ApiStateSnapshot, ApiStreamEnvelope, ApiStreamMessage, API_VERSION,
 };
 use crate::websocket::{websocket_accept_value, write_text_frame};
 use infinity_host::HostApiPort;
@@ -21,6 +21,13 @@ pub struct HostApiServer {
     accept_thread: Option<JoinHandle<()>>,
 }
 
+#[derive(Debug)]
+struct ApiRequestError {
+    status: u16,
+    code: String,
+    message: String,
+}
+
 impl HostApiServer {
     pub fn bind(bind: &str, service: Arc<dyn HostApiPort>) -> io::Result<Self> {
         let listener = TcpListener::bind(bind)?;
@@ -86,6 +93,14 @@ fn handle_connection(mut stream: TcpStream, service: Arc<dyn HostApiPort>) -> io
             let snapshot = service.snapshot();
             respond_json(&mut stream, 200, &ApiSnapshotResponse::from_snapshot(&snapshot))
         }
+        ("GET", "/api/v1/state") => {
+            let snapshot = service.snapshot();
+            respond_json(&mut stream, 200, &ApiStateResponse::from_snapshot(&snapshot))
+        }
+        ("GET", "/api/v1/preview") => {
+            let snapshot = service.snapshot();
+            respond_json(&mut stream, 200, &ApiPreviewResponse::from_snapshot(&snapshot))
+        }
         ("GET", "/api/v1/catalog") => {
             let snapshot = service.snapshot();
             respond_json(&mut stream, 200, &ApiCatalogResponse::from_snapshot(&snapshot))
@@ -102,9 +117,9 @@ fn handle_connection(mut stream: TcpStream, service: Arc<dyn HostApiPort>) -> io
             Ok(()) => Ok(()),
             Err(error) => respond_error(
                 &mut stream,
-                400,
-                "invalid_command",
-                format!("command request was rejected: {error}"),
+                error.status,
+                error.code,
+                error.message,
             ),
         },
         ("GET", "/") => respond_text(
@@ -148,16 +163,29 @@ fn handle_command_post(
     stream: &mut TcpStream,
     request: HttpRequest,
     service: Arc<dyn HostApiPort>,
-) -> io::Result<()> {
+) -> Result<(), ApiRequestError> {
     let parsed = serde_json::from_slice::<ApiCommandRequest>(&request.body)
-        .map_err(|error| io::Error::new(io::ErrorKind::InvalidData, error))?;
+        .map_err(|error| ApiRequestError {
+            status: 400,
+            code: "invalid_request_json".to_string(),
+            message: format!("command request body could not be parsed: {error}"),
+        })?;
     let request_id = parsed.request_id.clone();
-    let summary = parsed.summary();
+    let command_type = parsed.command.kind_label().to_string();
     let command = parsed
         .into_host_command()
-        .map_err(|error| io::Error::new(io::ErrorKind::InvalidInput, error))?;
-    service.send_command(command);
-    let snapshot = service.snapshot();
+        .map_err(|error| ApiRequestError {
+            status: 400,
+            code: "invalid_command".to_string(),
+            message: error,
+        })?;
+    let outcome = service
+        .send_command(command)
+        .map_err(|error| ApiRequestError {
+            status: 400,
+            code: error.code,
+            message: error.message,
+        })?;
     respond_json(
         stream,
         200,
@@ -165,10 +193,16 @@ fn handle_command_post(
             api_version: API_VERSION,
             accepted: true,
             request_id,
-            generated_at_millis: snapshot.generated_at_millis,
-            summary,
+            generated_at_millis: outcome.generated_at_millis,
+            command_type,
+            summary: outcome.summary,
         },
     )
+    .map_err(|error| ApiRequestError {
+        status: 500,
+        code: "response_write_failed".to_string(),
+        message: error.to_string(),
+    })
 }
 
 fn handle_websocket(
@@ -223,10 +257,7 @@ fn handle_websocket(
                 &mut stream,
                 sequence,
                 event.at_millis,
-                ApiStreamMessage::Event(ApiEventNotice {
-                    kind: ApiEventKind::Info,
-                    message: event.message,
-                }),
+                ApiStreamMessage::Event(event.into()),
             )?;
             sequence += 1;
         }
@@ -280,6 +311,7 @@ fn respond_text(
         200 => "OK",
         400 => "Bad Request",
         404 => "Not Found",
+        500 => "Internal Server Error",
         _ => "OK",
     };
     let response = format!(

crates/infinity_host_api/tests/contract.rs

@@ -5,8 +5,9 @@ use serde_json::Value;
 use std::collections::HashMap;
 use std::io::{Read, Write};
 use std::net::{Shutdown, SocketAddr, TcpStream};
+use std::path::PathBuf;
 use std::sync::Arc;
-use std::time::Duration;
+use std::time::{Duration, SystemTime, UNIX_EPOCH};
 
 fn sample_project() -> ProjectConfig {
     ProjectConfig::from_toml_str(include_str!("../../../config/project.example.toml"))
@@ -14,7 +15,15 @@ fn sample_project() -> ProjectConfig {
 }
 
 fn start_server() -> HostApiServer {
-    let service: Arc<dyn HostApiPort> = SimulationHostService::spawn_shared(sample_project());
+    let service: Arc<dyn HostApiPort> = Arc::new(SimulationHostService::new(sample_project()));
+    HostApiServer::bind("127.0.0.1:0", service).expect("server must bind")
+}
+
+fn start_server_with_runtime_state(path: &PathBuf) -> HostApiServer {
+    let service: Arc<dyn HostApiPort> = Arc::new(
+        SimulationHostService::try_new_with_persistence(sample_project(), path)
+            .expect("persistent service must initialize"),
+    );
     HostApiServer::bind("127.0.0.1:0", service).expect("server must bind")
 }
 
@@ -25,118 +34,183 @@ struct HttpResponse {
 }
 
 #[test]
-fn root_serves_creative_console_shell() {
+fn root_and_web_assets_target_the_versioned_api_contract() {
     let server = start_server();
-    let response = send_http_request(server.local_addr(), "GET", "/", None);
+    let html = send_http_request(server.local_addr(), "GET", "/", None);
+    let app_js = send_http_request(server.local_addr(), "GET", "/app.js", None);
 
-    assert_eq!(response.status_code, 200);
-    assert!(response
+    assert_eq!(html.status_code, 200);
+    assert!(html
         .headers
         .get("content-type")
         .expect("content-type header")
         .starts_with("text/html"));
-    assert!(response.body.contains("Infinity Vis / Creative Surface"));
-    assert!(response.body.contains("/app.js"));
+    assert!(html.body.contains("Preset Capture"));
+    assert!(html.body.contains("Creative Snapshots"));
+    assert!(html.body.contains("Event Stream"));
+
+    assert_eq!(app_js.status_code, 200);
+    assert!(app_js.body.contains("/api/v1/state"));
+    assert!(app_js.body.contains("/api/v1/preview"));
+    assert!(app_js.body.contains("save_preset"));
+    assert!(app_js.body.contains("save_creative_snapshot"));
 
     server.shutdown();
 }
 
 #[test]
-fn snapshot_endpoint_is_versioned_and_separates_state_and_preview() {
+fn state_preview_and_snapshot_endpoints_are_versioned_and_separated() {
     let server = start_server();
-    let response = send_http_request(server.local_addr(), "GET", "/api/v1/snapshot", None);
-    let body: Value = serde_json::from_str(&response.body).expect("snapshot json must parse");
-
-    assert_eq!(response.status_code, 200);
-    assert_eq!(body["api_version"], "v1");
-    assert_eq!(body["state"]["system"]["project_name"], "Infinity Vis");
-    assert_eq!(body["state"]["nodes"].as_array().map(Vec::len), Some(6));
-    assert_eq!(body["preview"]["panels"].as_array().map(Vec::len), Some(18));
-    assert!(body["state"]["active_scene"]["pattern_id"].is_string());
-
-    server.shutdown();
-}
-
-#[test]
-fn catalog_presets_and_groups_endpoints_return_expected_lists() {
-    let server = start_server();
-
-    let catalog = send_http_request(server.local_addr(), "GET", "/api/v1/catalog", None);
-    let presets = send_http_request(server.local_addr(), "GET", "/api/v1/presets", None);
-    let groups = send_http_request(server.local_addr(), "GET", "/api/v1/groups", None);
-
-    let catalog_body: Value = serde_json::from_str(&catalog.body).expect("catalog json");
-    let preset_body: Value = serde_json::from_str(&presets.body).expect("preset json");
-    let group_body: Value = serde_json::from_str(&groups.body).expect("group json");
-
-    assert_eq!(catalog.status_code, 200);
-    assert!(catalog_body["patterns"]
-        .as_array()
-        .expect("patterns array")
-        .iter()
-        .any(|pattern| pattern["pattern_id"] == "walking_pixel"));
-    assert!(preset_body["presets"]
-        .as_array()
-        .expect("presets array")
-        .iter()
-        .any(|preset| preset["preset_id"] == "ocean_gradient"));
-    assert!(group_body["groups"]
-        .as_array()
-        .expect("groups array")
-        .iter()
-        .any(|group| group["group_id"] == "top_panels"));
-
-    server.shutdown();
-}
-
-#[test]
-fn command_endpoint_applies_state_changes_and_rejects_invalid_payload() {
-    let server = start_server();
-
-    let response = send_http_request(
-        server.local_addr(),
-        "POST",
-        "/api/v1/command",
-        Some(
-            r#"{
-  "request_id": "contract-blackout",
-  "command": {
-    "type": "set_blackout",
-    "payload": {
-      "enabled": true
-    }
-  }
-}"#,
-        ),
-    );
-    let response_body: Value =
-        serde_json::from_str(&response.body).expect("command response must parse");
+    let state = send_http_request(server.local_addr(), "GET", "/api/v1/state", None);
+    let preview = send_http_request(server.local_addr(), "GET", "/api/v1/preview", None);
     let snapshot = send_http_request(server.local_addr(), "GET", "/api/v1/snapshot", None);
+
+    let state_body: Value = serde_json::from_str(&state.body).expect("state json");
+    let preview_body: Value = serde_json::from_str(&preview.body).expect("preview json");
     let snapshot_body: Value = serde_json::from_str(&snapshot.body).expect("snapshot json");
 
-    assert_eq!(response.status_code, 200);
-    assert_eq!(response_body["accepted"], true);
-    assert_eq!(response_body["request_id"], "contract-blackout");
-    assert_eq!(snapshot_body["state"]["global"]["blackout"], true);
+    assert_eq!(state.status_code, 200);
+    assert_eq!(state_body["api_version"], "v1");
+    assert!(state_body.get("state").is_some());
+    assert!(state_body.get("preview").is_none());
+    assert_eq!(state_body["state"]["nodes"].as_array().map(Vec::len), Some(6));
 
-    let invalid = send_http_request(
-        server.local_addr(),
-        "POST",
-        "/api/v1/command",
-        Some(r#"{"command":{"type":"set_blackout","payload":{}}}"#),
-    );
-    let invalid_body: Value =
-        serde_json::from_str(&invalid.body).expect("invalid response must parse");
+    assert_eq!(preview.status_code, 200);
+    assert_eq!(preview_body["api_version"], "v1");
+    assert!(preview_body.get("preview").is_some());
+    assert!(preview_body.get("state").is_none());
+    assert_eq!(preview_body["preview"]["panels"].as_array().map(Vec::len), Some(18));
 
-    assert_eq!(invalid.status_code, 400);
-    assert_eq!(invalid_body["api_version"], "v1");
-    assert_eq!(invalid_body["error"]["code"], "invalid_command");
+    assert_eq!(snapshot.status_code, 200);
+    assert_eq!(snapshot_body["api_version"], "v1");
+    assert!(snapshot_body.get("state").is_some());
+    assert!(snapshot_body.get("preview").is_some());
 
     server.shutdown();
 }
 
 #[test]
-fn websocket_stream_emits_snapshot_preview_and_event_messages() {
+fn command_flow_updates_group_parameters_transition_and_blackout() {
+    let server = start_server();
+
+    let responses = [
+        send_command_json(
+            server.local_addr(),
+            r#"{"command":{"type":"select_group","payload":{"group_id":"top_panels"}}}"#,
+        ),
+        send_command_json(
+            server.local_addr(),
+            r#"{"command":{"type":"set_scene_parameter","payload":{"key":"speed","value":{"kind":"scalar","value":2.25}}}}"#,
+        ),
+        send_command_json(
+            server.local_addr(),
+            r#"{"command":{"type":"set_transition_style","payload":{"style":"chase"}}}"#,
+        ),
+        send_command_json(
+            server.local_addr(),
+            r#"{"command":{"type":"set_transition_duration_ms","payload":{"duration_ms":320}}}"#,
+        ),
+        send_command_json(
+            server.local_addr(),
+            r#"{"command":{"type":"select_pattern","payload":{"pattern_id":"gradient"}}}"#,
+        ),
+    ];
+
+    for response in responses {
+        assert_eq!(response.status_code, 200);
+    }
+
+    let state = send_http_request(server.local_addr(), "GET", "/api/v1/state", None);
+    let state_body: Value = serde_json::from_str(&state.body).expect("state json");
+    assert_eq!(state_body["state"]["global"]["selected_group"], "top_panels");
+    assert_eq!(state_body["state"]["global"]["transition_style"], "chase");
+    assert_eq!(state_body["state"]["global"]["transition_duration_ms"], 320);
+    assert_eq!(state_body["state"]["active_scene"]["pattern_id"], "gradient");
+    assert!(state_body["state"]["active_scene"]["parameters"]
+        .as_array()
+        .expect("parameter array")
+        .iter()
+        .any(|parameter| parameter["key"] == "speed" && parameter["value"]["value"] == 2.25));
+
+    let blackout = send_command_json(
+        server.local_addr(),
+        r#"{"command":{"type":"set_blackout","payload":{"enabled":true}}}"#,
+    );
+    let blackout_body: Value = serde_json::from_str(&blackout.body).expect("blackout json");
+    assert_eq!(blackout.status_code, 200);
+    assert_eq!(blackout_body["command_type"], "set_blackout");
+
+    let preview = send_http_request(server.local_addr(), "GET", "/api/v1/preview", None);
+    let preview_body: Value = serde_json::from_str(&preview.body).expect("preview json");
+    assert!(preview_body["preview"]["panels"]
+        .as_array()
+        .expect("preview panels")
+        .iter()
+        .all(|panel| panel["energy_percent"] == 0 && panel["source"] == "blackout"));
+
+    server.shutdown();
+}
+
+#[test]
+fn presets_and_creative_snapshots_persist_across_restart() {
+    let runtime_state_path = unique_runtime_state_path("persistence");
+    let server = start_server_with_runtime_state(&runtime_state_path);
+
+    let _ = send_command_json(
+        server.local_addr(),
+        r#"{"command":{"type":"select_group","payload":{"group_id":"bottom_panels"}}}"#,
+    );
+    let _ = send_command_json(
+        server.local_addr(),
+        r#"{"command":{"type":"select_pattern","payload":{"pattern_id":"noise"}}}"#,
+    );
+    let _ = send_command_json(
+        server.local_addr(),
+        r#"{"command":{"type":"set_scene_parameter","payload":{"key":"grain","value":{"kind":"scalar","value":0.93}}}}"#,
+    );
+    let save_preset = send_command_json(
+        server.local_addr(),
+        r#"{"command":{"type":"save_preset","payload":{"preset_id":"user_noise_floor","overwrite":false}}}"#,
+    );
+    let save_snapshot = send_command_json(
+        server.local_addr(),
+        r#"{"command":{"type":"save_creative_snapshot","payload":{"snapshot_id":"variant_floor","label":"Variant Floor","overwrite":false}}}"#,
+    );
+    assert_eq!(save_preset.status_code, 200);
+    assert_eq!(save_snapshot.status_code, 200);
+    server.shutdown();
+
+    let restarted = start_server_with_runtime_state(&runtime_state_path);
+    let catalog = send_http_request(restarted.local_addr(), "GET", "/api/v1/catalog", None);
+    let state = send_http_request(restarted.local_addr(), "GET", "/api/v1/state", None);
+
+    let catalog_body: Value = serde_json::from_str(&catalog.body).expect("catalog json");
+    let state_body: Value = serde_json::from_str(&state.body).expect("state json");
+
+    assert!(catalog_body["presets"]
+        .as_array()
+        .expect("preset array")
+        .iter()
+        .any(|preset| preset["preset_id"] == "user_noise_floor" && preset["source"] == "runtime_user"));
+    assert!(catalog_body["creative_snapshots"]
+        .as_array()
+        .expect("snapshot array")
+        .iter()
+        .any(|snapshot| snapshot["snapshot_id"] == "variant_floor"));
+    assert_eq!(state_body["state"]["active_scene"]["pattern_id"], "noise");
+    assert_eq!(state_body["state"]["active_scene"]["target_group"], "bottom_panels");
+    assert!(state_body["state"]["active_scene"]["parameters"]
+        .as_array()
+        .expect("parameter array")
+        .iter()
+        .any(|parameter| parameter["key"] == "grain" && parameter["value"]["value"] == 0.93));
+
+    restarted.shutdown();
+    let _ = std::fs::remove_file(runtime_state_path);
+}
+
+#[test]
+fn websocket_stream_reports_event_codes_and_command_failures_stay_typed() {
     let server = start_server();
     let mut stream = open_websocket(server.local_addr());
 
@@ -148,43 +222,97 @@ fn websocket_stream_emits_snapshot_preview_and_event_messages() {
     let second_payload: Value = serde_json::from_str(&second_frame).expect("second ws frame");
     assert_eq!(second_payload["message"]["type"], "preview");
 
-    let _ = send_http_request(
+    let invalid = send_command_json(
         server.local_addr(),
-        "POST",
-        "/api/v1/command",
-        Some(
-            r#"{
-  "request_id": "contract-event",
-  "command": {
-    "type": "set_blackout",
-    "payload": {
-      "enabled": true
-    }
-  }
-}"#,
-        ),
+        r#"{"command":{"type":"recall_creative_snapshot","payload":{"snapshot_id":"does_not_exist"}}}"#,
     );
+    let invalid_body: Value = serde_json::from_str(&invalid.body).expect("invalid json");
+    assert_eq!(invalid.status_code, 400);
+    assert_eq!(invalid_body["error"]["code"], "unknown_creative_snapshot");
 
-    let mut saw_event = false;
+    let mut saw_warning = false;
     for _ in 0..8 {
         let frame = read_websocket_text_frame(&mut stream);
-        let payload: Value = serde_json::from_str(&frame).expect("ws event frame");
+        let payload: Value = serde_json::from_str(&frame).expect("ws frame");
         if payload["message"]["type"] == "event" {
-            saw_event = true;
+            saw_warning = true;
+            assert_eq!(payload["message"]["payload"]["kind"], "warning");
+            assert_eq!(payload["message"]["payload"]["code"], "unknown_creative_snapshot");
             assert!(payload["message"]["payload"]["message"]
                 .as_str()
                 .expect("event message")
-                .contains("blackout"));
+                .contains("does_not_exist"));
             break;
         }
     }
-
-    assert!(saw_event, "expected websocket event after command");
+    assert!(saw_warning, "expected warning event after failed command");
 
     let _ = stream.shutdown(Shutdown::Both);
     server.shutdown();
 }
 
+#[test]
+#[ignore = "longer load-oriented sequence for platform hardening"]
+fn load_sequence_keeps_state_preview_and_catalog_consistent() {
+    let server = start_server();
+    let patterns = ["solid_color", "gradient", "chase", "pulse", "noise"];
+    let groups = [None, Some("top_panels"), Some("middle_panels"), Some("bottom_panels")];
+
+    for index in 0..80 {
+        let pattern = patterns[index % patterns.len()];
+        let group = groups[index % groups.len()];
+        let brightness = ((index % 10) as f32) / 10.0;
+        let speed = 0.5 + (index % 6) as f32 * 0.25;
+
+        let _ = send_command_json(
+            server.local_addr(),
+            &format!(
+                r#"{{"command":{{"type":"select_pattern","payload":{{"pattern_id":"{pattern}"}}}}}}"#
+            ),
+        );
+        let _ = send_command_json(
+            server.local_addr(),
+            &format!(
+                r#"{{"command":{{"type":"set_master_brightness","payload":{{"value":{brightness}}}}}}}"#
+            ),
+        );
+        let _ = send_command_json(
+            server.local_addr(),
+            &format!(
+                r#"{{"command":{{"type":"set_scene_parameter","payload":{{"key":"speed","value":{{"kind":"scalar","value":{speed}}}}}}}}}"#
+            ),
+        );
+        let group_json = match group {
+            Some(group_id) => format!(r#""{group_id}""#),
+            None => "null".to_string(),
+        };
+        let _ = send_command_json(
+            server.local_addr(),
+            &format!(
+                r#"{{"command":{{"type":"select_group","payload":{{"group_id":{group_json}}}}}}}"#
+            ),
+        );
+
+        let state = send_http_request(server.local_addr(), "GET", "/api/v1/state", None);
+        let preview = send_http_request(server.local_addr(), "GET", "/api/v1/preview", None);
+        let catalog = send_http_request(server.local_addr(), "GET", "/api/v1/catalog", None);
+
+        let state_body: Value = serde_json::from_str(&state.body).expect("state json");
+        let preview_body: Value = serde_json::from_str(&preview.body).expect("preview json");
+        let catalog_body: Value = serde_json::from_str(&catalog.body).expect("catalog json");
+
+        assert_eq!(state_body["state"]["panels"].as_array().map(Vec::len), Some(18));
+        assert_eq!(preview_body["preview"]["panels"].as_array().map(Vec::len), Some(18));
+        assert!(catalog_body["patterns"].as_array().map(Vec::len).unwrap_or_default() >= 5);
+    }
+
+    server.shutdown();
+}
+
+fn send_command_json(addr: SocketAddr, body: &str) -> HttpResponse {
+    send_http_request(addr, "POST", "/api/v1/command", Some(body))
+}
+
 fn send_http_request(addr: SocketAddr, method: &str, path: &str, body: Option<&str>) -> HttpResponse {
     let body = body.unwrap_or("");
     let request = format!(
@@ -293,3 +421,11 @@ fn read_websocket_text_frame(stream: &mut TcpStream) -> String {
     stream.read_exact(&mut payload).expect("frame payload");
     String::from_utf8(payload).expect("frame utf8")
 }
+
+fn unique_runtime_state_path(label: &str) -> PathBuf {
+    let millis = SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .expect("system time")
+        .as_millis();
+    std::env::temp_dir().join(format!("infinity_vis_{label}_{millis}.json"))
+}

crates/infinity_host_ui/src/app.rs

@@ -69,7 +69,7 @@ fn draw_global_controls(ui: &mut egui::Ui, snapshot: &HostSnapshot, service: &Ar
         });
 
         if ui.add(blackout_button).clicked() {
-            service.send_command(HostCommand::SetBlackout(!blackout));
+            let _ = service.send_command(HostCommand::SetBlackout(!blackout));
         }
 
         let mut brightness = snapshot.global.master_brightness;
@@ -80,7 +80,7 @@ fn draw_global_controls(ui: &mut egui::Ui, snapshot: &HostSnapshot, service: &Ar
             )
             .changed()
         {
-            service.send_command(HostCommand::SetMasterBrightness(brightness));
+            let _ = service.send_command(HostCommand::SetMasterBrightness(brightness));
         }
 
         let selected_pattern = snapshot.global.selected_pattern.clone();
@@ -93,7 +93,7 @@ fn draw_global_controls(ui: &mut egui::Ui, snapshot: &HostSnapshot, service: &Ar
                         .selectable_label(selected_pattern == *pattern, pattern)
                         .clicked()
                     {
-                        service.send_command(HostCommand::SelectPattern(pattern.clone()));
+                        let _ = service.send_command(HostCommand::SelectPattern(pattern.clone()));
                     }
                 }
             });
@@ -183,7 +183,7 @@ fn draw_panel_mapping(
                             }
                         });
                         if ui.button("Walk 106").clicked() {
-                            service.send_command(HostCommand::TriggerPanelTest {
+                            let _ = service.send_command(HostCommand::TriggerPanelTest {
                                 target: PanelTarget {
                                     node_id: panel.target.node_id.clone(),
                                     panel_position: panel.target.panel_position.clone(),

docs/architecture.md

@@ -55,6 +55,13 @@ Every surface must talk to the same host API:
 - CLI inspection
 - future grandMA adapter
 
+The host core now also carries a runtime show store and persistence layer for:
+
+- saved presets
+- runtime user groups
+- active scene state
+- creative snapshots and variants
+
 The current software-first implementation uses a simulation-backed host API so looks, presets, parameters, and grouping can be developed before real node activation.
 
 ## Modes
@@ -104,5 +111,5 @@ The codebase deliberately blocks activation when these remain unresolved:
 1. Expand creative authoring on top of the now-versioned host API and web UI
 2. Keep the engineering GUI focused on mapping, diagnostics, topology, and admin
 3. Implement transport adapters without coupling them to any single frontend
-4. Add future external show-control bridges such as grandMA on the same API boundary
+4. Add future external show-control bridges such as grandMA on the same API boundary and generic adapter interface
 5. Keep hardware activation behind explicit later validation gates

docs/build_and_deploy.md

@@ -12,13 +12,13 @@ Suggested commands:
 ```powershell
 cargo test
 cargo run -p infinity_host -- snapshot --config config/project.example.toml
-cargo run -p infinity_host_api -- --config config/project.example.toml --bind 127.0.0.1:9001
+cargo run -p infinity_host_api -- --config config/project.example.toml --bind 127.0.0.1:9001 --runtime-state data/runtime_state.json
 cargo run -p infinity_host_ui
 cargo run -p infinity_host -- validate --config config/project.example.toml --mode structural
 cargo run -p infinity_host -- plan-boot-scene --config config/project.example.toml --preset-id safe_static_blue
 ```
 
-The host API server now exposes the common software-first control boundary over HTTP and WebSocket. The creative web UI is served directly from the same process at `http://127.0.0.1:9001/`.
+The host API server now exposes the common software-first control boundary over HTTP and WebSocket. The creative web UI is served directly from the same process at `http://127.0.0.1:9001/`. Runtime creative data such as saved presets, groups, active scene state, and creative snapshots are persisted to `data/runtime_state.json` by default.
 
 The native engineering UI and the CLI snapshot continue to run against the same simulation-backed host core so looks, presets, grouping, and parameter flow can be exercised before transport and firmware integration are complete.
 

docs/host_api.md

@@ -2,58 +2,107 @@
 
 ## Purpose
 
-The host API is the stable external boundary for:
+The host API is the stable external product boundary for:
 
 - the creative web UI
-- the existing engineering GUI
-- future external show-control adapters such as grandMA
+- the native engineering GUI
+- future remote operator clients
+- later external show-control adapters such as a grandMA bridge
 
-The core rule stays unchanged:
+The realtime rule remains strict:
 
 - the API is a control and observation layer
-- the realtime engine remains the timing authority
-- no surface is allowed to become the LED clock
+- the host core remains the timing authority
+- no frontend or external adapter is allowed to become the LED clock
 
-## Current Implementation
+## Runtime Components
 
-Runtime pieces:
+Core and API implementation:
 
 - `crates/infinity_host/src/control.rs`
 - `crates/infinity_host/src/scene.rs`
+- `crates/infinity_host/src/show_store.rs`
 - `crates/infinity_host/src/simulation.rs`
+- `crates/infinity_host/src/external_control.rs`
 - `crates/infinity_host_api/src/dto.rs`
 - `crates/infinity_host_api/src/server.rs`
 
-The network-facing server is started with:
+Server startup:
 
 ```powershell
-cargo run -p infinity_host_api -- --config config/project.example.toml --bind 127.0.0.1:9001
+cargo run -p infinity_host_api -- --config config/project.example.toml --bind 127.0.0.1:9001 --runtime-state data/runtime_state.json
 ```
 
-Creative web UI V1 is served by the same process at:
+Creative web UI V1 is served by the same process:
 
 ```text
 http://127.0.0.1:9001/
 ```
 
-## Versioning
+## Versioning Policy
 
-- HTTP and WebSocket routes are versioned under `/api/v1`
-- responses include `api_version: "v1"`
-- the external DTOs are intentionally not a direct 1:1 dump of internal core structs
+The current public contract is `v1`.
 
-## Endpoint Contract
+Rules:
 
-### GET `/api/v1/snapshot`
+- all public HTTP and WebSocket routes are namespaced under `/api/v1`
+- every response body carries `api_version: "v1"`
+- additive fields are allowed inside `v1`
+- semantic breaking changes require a new version namespace
+- external consumers must treat undocumented internal-only fields as unstable and ignore them
 
-Returns the current state and preview in one response.
+## Stable External Models
+
+Stable external response families:
+
+- command response
+- state snapshot
+- preview snapshot
+- combined snapshot
+- catalog
+- event stream
+- typed error object
+
+Stable external command families:
+
+- global control
+- pattern and preset selection
+- group targeting
+- scene parameter updates
+- transition configuration
+- preset persistence
+- creative snapshot persistence and recall
+- panel test trigger
+
+## Internal Versus External Fields
+
+External and stable in `v1`:
+
+- every field defined in `crates/infinity_host_api/src/dto.rs`
+- route names and payload shapes documented below
+- error object shape `{ api_version, error: { code, message } }`
+- event stream envelope shape `{ api_version, sequence, generated_at_millis, message }`
+
+Internal and not part of the API contract:
+
+- the exact shape of `HostSnapshot` in `crates/infinity_host/src/control.rs`
+- simulation-only storage layout in `data/runtime_state.json`
+- internal event history buffering size
+- internal scene library structures in `show_store.rs`
+- engineering-GUI-specific rendering or polling behavior
+
+## HTTP Endpoints
+
+### GET `/api/v1/state`
+
+Returns only the stable state snapshot.
 
 Example:
 
 ```json
 {
   "api_version": "v1",
-  "generated_at_millis": 241,
+  "generated_at_millis": 512,
   "state": {
     "system": {
       "project_name": "Infinity Vis",
@@ -63,186 +112,42 @@ Example:
     "global": {
       "blackout": false,
       "master_brightness": 0.2,
-      "selected_pattern": "solid_color",
-      "selected_group": null,
-      "transition_duration_ms": 150
+      "selected_pattern": "gradient",
+      "selected_group": "top_panels",
+      "transition_duration_ms": 320,
+      "transition_style": "chase"
     },
     "engine": {
       "logic_hz": 120,
       "frame_hz": 60,
       "preview_hz": 15,
-      "uptime_ms": 241,
-      "frame_index": 14,
+      "uptime_ms": 512,
+      "frame_index": 30,
       "dropped_frames": 0,
-      "active_transition": null
-    },
-    "active_scene": {
-      "preset_id": null,
-      "pattern_id": "solid_color",
-      "seed": 100,
-      "palette": [
-        "#ffffff"
-      ],
-      "parameters": [],
-      "target_group": null,
-      "blackout": false
+      "active_transition": {
+        "style": "chase",
+        "from_pattern_id": "solid_color",
+        "to_pattern_id": "gradient",
+        "duration_ms": 320,
+        "progress": 0.28
       }
-  },
+    }
+  }
+}
+```
+
+### GET `/api/v1/preview`
+
+Returns only the stable preview snapshot.
+
+Example:
+
+```json
+{
+  "api_version": "v1",
+  "generated_at_millis": 512,
   "preview": {
-    "generated_at_millis": 241,
-    "panels": [
-      {
-        "node_id": "node-01",
-        "panel_position": "top",
-        "representative_color_hex": "#33CCFF",
-        "sample_led_hex": [
-          "#33CCFF",
-          "#28A3CC",
-          "#1E7A99"
-        ],
-        "energy_percent": 28,
-        "source": "scene"
-      }
-    ]
-  }
-}
-```
-
-### GET `/api/v1/catalog`
-
-Returns the creative catalog:
-
-- patterns
-- presets
-- groups
-
-### GET `/api/v1/presets`
-
-Returns only preset summaries.
-
-Example:
-
-```json
-{
-  "api_version": "v1",
-  "presets": [
-    {
-      "preset_id": "ocean_gradient",
-      "pattern_id": "gradient",
-      "target_group": null,
-      "transition_duration_ms": 320
-    }
-  ]
-}
-```
-
-### GET `/api/v1/groups`
-
-Returns only group summaries.
-
-Example:
-
-```json
-{
-  "api_version": "v1",
-  "groups": [
-    {
-      "group_id": "top_panels",
-      "member_count": 6,
-      "tags": [
-        "row",
-        "top"
-      ]
-    }
-  ]
-}
-```
-
-### POST `/api/v1/command`
-
-Accepts a versioned command envelope.
-
-Example request:
-
-```json
-{
-  "request_id": "web-1713352662000",
-  "command": {
-    "type": "set_master_brightness",
-    "payload": {
-      "value": 0.42
-    }
-  }
-}
-```
-
-Example response:
-
-```json
-{
-  "api_version": "v1",
-  "accepted": true,
-  "request_id": "web-1713352662000",
-  "generated_at_millis": 522,
-  "summary": "master brightness set to 42%"
-}
-```
-
-Errors use a stable error object:
-
-```json
-{
-  "api_version": "v1",
-  "error": {
-    "code": "invalid_command",
-    "message": "command request was rejected: missing field `enabled`"
-  }
-}
-```
-
-### WS `/api/v1/stream`
-
-The WebSocket stream emits envelopes with a monotonic sequence and a typed payload.
-
-Stream message types:
-
-- `snapshot`
-- `preview`
-- `event`
-
-Example snapshot envelope:
-
-```json
-{
-  "api_version": "v1",
-  "sequence": 17,
-  "generated_at_millis": 875,
-  "message": {
-    "type": "snapshot",
-    "payload": {
-      "global": {
-        "blackout": false,
-        "master_brightness": 0.35,
-        "selected_pattern": "gradient",
-        "selected_group": "top_panels",
-        "transition_duration_ms": 320
-      }
-    }
-  }
-}
-```
-
-Example preview envelope:
-
-```json
-{
-  "api_version": "v1",
-  "sequence": 18,
-  "generated_at_millis": 875,
-  "message": {
-    "type": "preview",
-    "payload": {
-      "generated_at_millis": 875,
+    "generated_at_millis": 512,
     "panels": [
       {
         "node_id": "node-01",
@@ -258,11 +163,125 @@ Example preview envelope:
       }
     ]
   }
+}
+```
+
+### GET `/api/v1/snapshot`
+
+Returns the convenience composition of `state` plus `preview`.
+
+This route exists for lightweight clients and debugging. Consumers that want strict separation should prefer `GET /api/v1/state` and `GET /api/v1/preview`.
+
+### GET `/api/v1/catalog`
+
+Returns the stable creative library:
+
+- patterns
+- presets
+- groups
+- creative snapshots
+
+Example preset summary:
+
+```json
+{
+  "preset_id": "ocean_gradient",
+  "pattern_id": "gradient",
+  "target_group": null,
+  "transition_duration_ms": 320,
+  "transition_style": "crossfade",
+  "source": "built_in"
+}
+```
+
+Example creative snapshot summary:
+
+```json
+{
+  "snapshot_id": "variant_floor",
+  "label": "Variant Floor",
+  "pattern_id": "noise",
+  "target_group": "bottom_panels",
+  "transition_duration_ms": 220,
+  "transition_style": "chase",
+  "saved_at_unix_ms": 1760000000000
+}
+```
+
+### GET `/api/v1/presets`
+
+Returns only preset summaries.
+
+### GET `/api/v1/groups`
+
+Returns only group summaries.
+
+### POST `/api/v1/command`
+
+Accepts one versioned command envelope.
+
+Example request:
+
+```json
+{
+  "request_id": "web-1713352662000",
+  "command": {
+    "type": "save_creative_snapshot",
+    "payload": {
+      "snapshot_id": "variant_floor",
+      "label": "Variant Floor",
+      "overwrite": false
+    }
   }
 }
 ```
 
-Example event envelope:
+Example response:
+
+```json
+{
+  "api_version": "v1",
+  "accepted": true,
+  "request_id": "web-1713352662000",
+  "generated_at_millis": 522,
+  "command_type": "save_creative_snapshot",
+  "summary": "creative snapshot saved: variant_floor"
+}
+```
+
+## Stable Error Object
+
+All API failures return:
+
+```json
+{
+  "api_version": "v1",
+  "error": {
+    "code": "unknown_creative_snapshot",
+    "message": "creative snapshot 'does_not_exist' does not exist"
+  }
+}
+```
+
+Stable `v1` error families currently include:
+
+- `invalid_request_json`
+- `invalid_command`
+- `unknown_group`
+- `unknown_preset`
+- `unknown_creative_snapshot`
+- `preset_exists`
+- `snapshot_exists`
+- `group_exists`
+- `persist_failed`
+- `missing_websocket_key`
+- `not_found`
+
+## WebSocket Event Stream
+
+### WS `/api/v1/stream`
+
+The stream emits a typed envelope with a monotonic sequence counter:
 
 ```json
 {
@@ -272,16 +291,29 @@ Example event envelope:
   "message": {
     "type": "event",
     "payload": {
-      "kind": "info",
-      "message": "preset recalled: ocean_gradient"
+      "kind": "warning",
+      "code": "unknown_creative_snapshot",
+      "message": "creative snapshot 'does_not_exist' does not exist"
     }
   }
 }
 ```
 
-## Supported Commands
+Stable message types:
 
-The current API command set covers:
+- `snapshot`
+- `preview`
+- `event`
+
+Stable event kinds:
+
+- `info`
+- `warning`
+- `error`
+
+## Guaranteed Commands In `v1`
+
+Guaranteed control commands:
 
 - `set_blackout`
 - `set_master_brightness`
@@ -290,53 +322,76 @@ The current API command set covers:
 - `select_group`
 - `set_scene_parameter`
 - `set_transition_duration_ms`
+- `set_transition_style`
 - `trigger_panel_test`
 
-This is intentionally enough for:
+Guaranteed persistence and creative-library commands:
 
-- creative look development in the web UI
-- engineering test triggers in the native GUI
-- future external show-control translation layers
+- `save_preset`
+- `save_creative_snapshot`
+- `recall_creative_snapshot`
+- `upsert_group`
 
-## Web UI V1
+## Persistence Behavior
 
-The first creative web UI is intentionally limited to:
+The simulation-backed host service now persists runtime-facing creative data to `data/runtime_state.json` by default.
 
-- pattern selection
-- preset recall
-- group selection
-- global brightness
-- blackout
-- transition duration
-- scene parameter controls driven from the API schema
-- panel preview
-- snapshot display
-- event feed
+Persisted data includes:
 
-It does not absorb mapping, topology, or hardware-diagnostic workflows. Those stay in the native engineering UI.
+- active scene
+- global blackout and brightness state
+- transition duration and style
+- runtime user presets
+- runtime user groups
+- creative snapshots and variants
 
-## Contract Tests
+This persistence file is an internal runtime artifact, not the public API contract.
 
-The API contract is currently verified in:
+## External Show Control Adapter Boundary
+
+The generic internal adapter surface lives in:
+
+- `crates/infinity_host/src/external_control.rs`
+
+Key rule:
+
+- future adapters may only translate external intent into the defined host command surface
+- they must not reach into simulation internals, UI state, or hardware driver details directly
+
+## Contract And Integration Coverage
+
+Current software-side hardening lives in:
 
 - `crates/infinity_host_api/tests/contract.rs`
+- `crates/infinity_host/src/show_store.rs` tests
+- `crates/infinity_host/src/simulation.rs` tests
 
-Covered paths:
+Covered flows include:
 
-- root web shell
-- `GET /api/v1/snapshot`
-- `GET /api/v1/catalog`
-- `GET /api/v1/presets`
-- `GET /api/v1/groups`
-- `POST /api/v1/command`
-- `WS /api/v1/stream`
+- state, preview, snapshot, catalog, presets, and groups endpoints
+- command success and typed command failure
+- WebSocket snapshot, preview, and event messages
+- group targeting
+- parameter updates
+- transition configuration
+- blackout
+- preset save
+- creative snapshot save and recall
+- persistence across restart
+- a longer ignored load-oriented sequence for platform hardening
 
-## Future Direction
+## Web UI Scope
 
-Next adapters should be built on this boundary instead of reaching into the host core directly.
+The current web UI intentionally focuses on creative use:
 
-That includes:
+- pattern and preset selection
+- group targeting
+- transition configuration
+- scene parameters
+- preset save and overwrite
+- creative snapshot save and recall
+- preview
+- raw snapshot display
+- filterable event feed
 
-- a richer web authoring surface
-- remote operator clients
-- a grandMA bridge that translates external show control into host API commands
+Mapping, topology diagnostics, panel-test administration, and low-level node status remain primarily in the native engineering GUI.

web/v1/app.js

@@ -1,9 +1,8 @@
 (function () {
   const apiState = {
-    snapshot: null,
+    stateResponse: null,
+    previewResponse: null,
     catalog: null,
-    presets: [],
-    groups: [],
     events: [],
     ws: null,
     commandTimers: new Map(),
@@ -18,15 +17,27 @@
     patternSelect: document.getElementById("pattern-select"),
     transitionSlider: document.getElementById("transition-slider"),
     transitionValue: document.getElementById("transition-value"),
+    transitionStyleSelect: document.getElementById("transition-style-select"),
     brightnessSlider: document.getElementById("brightness-slider"),
     brightnessValue: document.getElementById("brightness-value"),
     blackoutButton: document.getElementById("blackout-button"),
     presetList: document.getElementById("preset-list"),
+    presetIdInput: document.getElementById("preset-id-input"),
+    presetOverwriteInput: document.getElementById("preset-overwrite-input"),
+    savePresetButton: document.getElementById("save-preset-button"),
+    groupFilterInput: document.getElementById("group-filter-input"),
     groupList: document.getElementById("group-list"),
+    snapshotIdInput: document.getElementById("snapshot-id-input"),
+    snapshotLabelInput: document.getElementById("snapshot-label-input"),
+    snapshotOverwriteInput: document.getElementById("snapshot-overwrite-input"),
+    saveSnapshotButton: document.getElementById("save-snapshot-button"),
+    snapshotList: document.getElementById("snapshot-list"),
     sceneParams: document.getElementById("scene-params"),
     previewGrid: document.getElementById("preview-grid"),
     summaryCards: document.getElementById("summary-cards"),
     snapshotJson: document.getElementById("snapshot-json"),
+    eventKindFilter: document.getElementById("event-kind-filter"),
+    eventSearchFilter: document.getElementById("event-search-filter"),
     eventList: document.getElementById("event-list"),
   };
 
@@ -49,12 +60,19 @@
     dom.transitionSlider.addEventListener("input", (event) => {
       const value = Number(event.target.value);
       dom.transitionValue.textContent = `${value} ms`;
-      debounceCommand("transition", {
+      debounceCommand("transition-duration", {
         type: "set_transition_duration_ms",
         payload: { duration_ms: value },
       });
     });
 
+    dom.transitionStyleSelect.addEventListener("change", (event) => {
+      sendCommand({
+        type: "set_transition_style",
+        payload: { style: event.target.value },
+      });
+    });
+
     dom.brightnessSlider.addEventListener("input", (event) => {
       const value = Number(event.target.value);
       dom.brightnessValue.textContent = `${Math.round(value * 100)}%`;
@@ -65,36 +83,83 @@
     });
 
     dom.blackoutButton.addEventListener("click", () => {
-      const enabled = !(apiState.snapshot?.state?.global?.blackout ?? false);
+      const enabled = !(apiState.stateResponse?.state?.global?.blackout ?? false);
       sendCommand({
         type: "set_blackout",
         payload: { enabled },
       });
     });
+
+    dom.savePresetButton.addEventListener("click", async () => {
+      const presetId = dom.presetIdInput.value.trim();
+      if (!presetId) {
+        pushEvent({
+          at: new Date().toLocaleTimeString(),
+          kind: "warning",
+          code: "preset_id_required",
+          message: "Preset ID is required before saving.",
+        });
+        return;
+      }
+
+      await sendCommand({
+        type: "save_preset",
+        payload: {
+          preset_id: presetId,
+          overwrite: dom.presetOverwriteInput.checked,
+        },
+      });
+    });
+
+    dom.saveSnapshotButton.addEventListener("click", async () => {
+      const snapshotId = dom.snapshotIdInput.value.trim();
+      if (!snapshotId) {
+        pushEvent({
+          at: new Date().toLocaleTimeString(),
+          kind: "warning",
+          code: "snapshot_id_required",
+          message: "Snapshot ID is required before saving a creative variant.",
+        });
+        return;
+      }
+
+      await sendCommand({
+        type: "save_creative_snapshot",
+        payload: {
+          snapshot_id: snapshotId,
+          label: dom.snapshotLabelInput.value.trim() || null,
+          overwrite: dom.snapshotOverwriteInput.checked,
+        },
+      });
+    });
+
+    dom.groupFilterInput.addEventListener("input", () => renderGroups());
+    dom.eventKindFilter.addEventListener("change", () => renderEvents());
+    dom.eventSearchFilter.addEventListener("input", () => renderEvents());
   }
 
   async function refreshAll() {
     setConnectionState("connecting", "loading");
     try {
-      const [snapshot, catalog, presets, groups] = await Promise.all([
-        fetchJson("/api/v1/snapshot"),
+      const [stateResponse, previewResponse, catalog] = await Promise.all([
+        fetchJson("/api/v1/state"),
+        fetchJson("/api/v1/preview"),
         fetchJson("/api/v1/catalog"),
-        fetchJson("/api/v1/presets"),
-        fetchJson("/api/v1/groups"),
       ]);
 
-      apiState.snapshot = snapshot;
+      apiState.stateResponse = stateResponse;
+      apiState.previewResponse = previewResponse;
       apiState.catalog = catalog;
-      apiState.presets = presets.presets || catalog.presets || [];
-      apiState.groups = groups.groups || catalog.groups || [];
 
       renderAll();
-      setConnectionState("online", "HTTP snapshot synced");
+      setConnectionState("online", "HTTP sync");
     } catch (error) {
       console.error(error);
       setConnectionState("offline", "snapshot fetch failed");
       pushEvent({
         at: new Date().toLocaleTimeString(),
+        kind: "error",
+        code: "http_refresh_failed",
         message: `HTTP refresh failed: ${error.message}`,
       });
     }
@@ -110,6 +175,8 @@
       setConnectionState("online", "stream connected");
       pushEvent({
         at: new Date().toLocaleTimeString(),
+        kind: "info",
+        code: "stream_connected",
         message: "WebSocket stream connected",
       });
     });
@@ -123,6 +190,8 @@
       setConnectionState("offline", "stream disconnected");
       pushEvent({
         at: new Date().toLocaleTimeString(),
+        kind: "warning",
+        code: "stream_reconnect",
         message: "WebSocket stream closed, retrying",
       });
       window.setTimeout(connectStream, 1500);
@@ -139,26 +208,22 @@
       return;
     }
 
-    if (!apiState.snapshot) {
-      apiState.snapshot = {
+    if (message.type === "snapshot") {
+      apiState.stateResponse = {
         api_version: envelope.api_version,
         generated_at_millis: envelope.generated_at_millis,
-        state: null,
-        preview: null,
+        state: message.payload,
       };
-    }
-
-    if (message.type === "snapshot") {
-      apiState.snapshot.api_version = envelope.api_version;
-      apiState.snapshot.generated_at_millis = envelope.generated_at_millis;
-      apiState.snapshot.state = message.payload;
       renderState();
       return;
     }
 
     if (message.type === "preview") {
-      apiState.snapshot.preview = message.payload;
-      apiState.snapshot.generated_at_millis = envelope.generated_at_millis;
+      apiState.previewResponse = {
+        api_version: envelope.api_version,
+        generated_at_millis: envelope.generated_at_millis,
+        preview: message.payload,
+      };
       renderPreview();
       renderSnapshotJson();
       return;
@@ -167,6 +232,8 @@
     if (message.type === "event") {
       pushEvent({
         at: `${envelope.generated_at_millis} ms`,
+        kind: message.payload.kind || "info",
+        code: message.payload.code || null,
         message: message.payload.message,
       });
     }
@@ -184,15 +251,21 @@
       });
       pushEvent({
         at: new Date().toLocaleTimeString(),
+        kind: "info",
+        code: response.command_type,
         message: response.summary,
       });
       await refreshAll();
+      return response;
     } catch (error) {
       console.error(error);
       pushEvent({
         at: new Date().toLocaleTimeString(),
+        kind: "error",
+        code: "command_failed",
         message: `Command failed: ${error.message}`,
       });
+      return null;
     }
   }
 
@@ -232,17 +305,16 @@
   }
 
   function renderState() {
-    if (!apiState.snapshot?.state) {
+    const state = apiState.stateResponse?.state;
+    if (!state) {
       return;
     }
 
-    const snapshot = apiState.snapshot;
-    const state = snapshot.state;
     const global = state.global;
     const scene = state.active_scene;
 
     dom.projectName.textContent = state.system.project_name;
-    dom.topologyLabel.textContent = `${state.system.topology_label} / API ${snapshot.api_version}`;
+    dom.topologyLabel.textContent = `${state.system.topology_label} / API ${apiState.stateResponse.api_version}`;
 
     dom.patternSelect.innerHTML = "";
     (apiState.catalog?.patterns || []).forEach((pattern) => {
@@ -255,22 +327,23 @@
 
     dom.transitionSlider.value = String(global.transition_duration_ms);
     dom.transitionValue.textContent = `${global.transition_duration_ms} ms`;
+    dom.transitionStyleSelect.value = global.transition_style;
     dom.brightnessSlider.value = String(global.master_brightness);
     dom.brightnessValue.textContent = `${Math.round(global.master_brightness * 100)}%`;
     dom.blackoutButton.textContent = global.blackout ? "Release blackout" : "Enable blackout";
     dom.blackoutButton.classList.toggle("is-active", global.blackout);
 
-    renderPresetButtons(scene, global);
-    renderGroupButtons(global);
+    renderPresets(scene);
+    renderGroups(global);
+    renderCreativeSnapshots();
     renderSceneParameters(scene);
-    renderSummaryCards(state, snapshot.generated_at_millis);
+    renderSummaryCards(state);
     renderSnapshotJson();
-    dom.previewUpdated.textContent = `${snapshot.generated_at_millis} ms`;
   }
 
-  function renderPresetButtons(scene) {
+  function renderPresets(scene) {
     dom.presetList.innerHTML = "";
-    const presets = apiState.presets || [];
+    const presets = apiState.catalog?.presets || [];
     if (!presets.length) {
       dom.presetList.innerHTML = '<div class="empty-state">No presets available.</div>';
       return;
@@ -283,7 +356,7 @@
       button.classList.toggle("active", scene.preset_id === preset.preset_id);
       button.innerHTML = `
         <strong>${preset.preset_id}</strong>
-        <div class="pill-subtext">${preset.pattern_id} / ${preset.transition_duration_ms} ms</div>
+        <div class="pill-subtext">${preset.pattern_id} / ${preset.transition_style} / ${preset.source}</div>
       `;
       button.addEventListener("click", () =>
         sendCommand({
@@ -295,8 +368,18 @@
     });
   }
 
-  function renderGroupButtons(global) {
+  function renderGroups(global) {
     dom.groupList.innerHTML = "";
+    const filterValue = dom.groupFilterInput.value.trim().toLowerCase();
+    const groups = (apiState.catalog?.groups || []).filter((group) => {
+      if (!filterValue) {
+        return true;
+      }
+      return (
+        group.group_id.toLowerCase().includes(filterValue) ||
+        (group.tags || []).some((tag) => tag.toLowerCase().includes(filterValue))
+      );
+    });
 
     const allButton = document.createElement("button");
     allButton.type = "button";
@@ -311,14 +394,22 @@
     );
     dom.groupList.appendChild(allButton);
 
-    (apiState.groups || []).forEach((group) => {
+    if (!groups.length) {
+      const empty = document.createElement("div");
+      empty.className = "empty-state";
+      empty.textContent = "No groups match the current filter.";
+      dom.groupList.appendChild(empty);
+      return;
+    }
+
+    groups.forEach((group) => {
       const button = document.createElement("button");
       button.type = "button";
       button.className = "group-button";
       button.classList.toggle("active", group.group_id === global.selected_group);
       button.innerHTML = `
         <strong>${group.group_id}</strong>
-        <div class="pill-subtext">${group.member_count} members</div>
+        <div class="pill-subtext">${group.member_count} members / ${group.source}</div>
       `;
       button.addEventListener("click", () =>
         sendCommand({
@@ -330,6 +421,43 @@
     });
   }
 
+  function renderCreativeSnapshots() {
+    dom.snapshotList.innerHTML = "";
+    const snapshots = apiState.catalog?.creative_snapshots || [];
+    if (!snapshots.length) {
+      dom.snapshotList.innerHTML =
+        '<div class="empty-state">No creative snapshots saved yet.</div>';
+      return;
+    }
+
+    snapshots.forEach((snapshot) => {
+      const card = document.createElement("article");
+      card.className = "snapshot-card";
+      card.innerHTML = `
+        <div class="snapshot-card-header">
+          <div>
+            <strong>${snapshot.label || snapshot.snapshot_id}</strong>
+            <div class="preview-meta">${snapshot.snapshot_id}</div>
+          </div>
+          <button type="button" class="ghost-button">Recall</button>
+        </div>
+        <div class="snapshot-meta-row">
+          <span class="meta-chip">${snapshot.pattern_id}</span>
+          <span class="meta-chip">${snapshot.transition_style}</span>
+          <span class="meta-chip">${snapshot.transition_duration_ms} ms</span>
+          <span class="meta-chip">${snapshot.target_group || "all_panels"}</span>
+        </div>
+      `;
+      card.querySelector("button").addEventListener("click", () =>
+        sendCommand({
+          type: "recall_creative_snapshot",
+          payload: { snapshot_id: snapshot.snapshot_id },
+        })
+      );
+      dom.snapshotList.appendChild(card);
+    });
+  }
+
   function renderSceneParameters(scene) {
     dom.sceneParams.innerHTML = "";
     const parameters = scene.parameters || [];
@@ -417,7 +545,7 @@
   }
 
   function renderPreview() {
-    const preview = apiState.snapshot?.preview;
+    const preview = apiState.previewResponse?.preview;
     dom.previewGrid.innerHTML = "";
     if (!preview?.panels?.length) {
       dom.previewGrid.innerHTML =
@@ -425,6 +553,7 @@
       return;
     }
 
+    dom.previewUpdated.textContent = `${apiState.previewResponse.generated_at_millis} ms`;
     const panels = [...preview.panels].sort(comparePreviewPanels);
     panels.forEach((panel) => {
       const card = document.createElement("article");
@@ -439,6 +568,7 @@
           <strong>${panel.energy_percent}%</strong>
         </div>
         <div class="preview-swatch"></div>
+        <div class="energy-bar"><span style="--energy-width: ${panel.energy_percent}%"></span></div>
         <div class="sample-row">
           ${panel.sample_led_hex
             .map(
@@ -452,11 +582,12 @@
     });
   }
 
-  function renderSummaryCards(state, generatedAtMillis) {
+  function renderSummaryCards(state) {
     const scene = state.active_scene;
     const global = state.global;
     const engine = state.engine;
     const nodeStats = summarizeNodes(state.nodes || []);
+    const creativeSnapshotCount = (apiState.catalog?.creative_snapshots || []).length;
 
     const cards = [
       {
@@ -467,11 +598,11 @@
       {
         label: "Group Target",
         value: scene.target_group || "all_panels",
-        detail: `${(apiState.groups || []).length} groups available`,
+        detail: `${(apiState.catalog?.groups || []).length} groups available`,
       },
       {
         label: "Transition",
-        value: `${global.transition_duration_ms} ms`,
+        value: `${global.transition_style} / ${global.transition_duration_ms} ms`,
         detail: engine.active_transition
           ? `${engine.active_transition.style} ${Math.round(engine.active_transition.progress * 100)}%`
           : "idle",
@@ -492,9 +623,9 @@
         detail: `${nodeStats.degraded} degraded / ${nodeStats.offline} offline`,
       },
       {
-        label: "Preview Timestamp",
-        value: `${generatedAtMillis} ms`,
-        detail: `${state.system.schema_version} schema`,
+        label: "Creative Snapshots",
+        value: `${creativeSnapshotCount}`,
+        detail: `${(apiState.catalog?.presets || []).length} presets in library`,
       },
     ];
 
@@ -512,28 +643,55 @@
   }
 
   function renderSnapshotJson() {
-    dom.snapshotJson.textContent = apiState.snapshot
-      ? JSON.stringify(apiState.snapshot, null, 2)
-      : "No snapshot loaded.";
+    dom.snapshotJson.textContent = JSON.stringify(buildComposedSnapshot(), null, 2);
+  }
+
+  function buildComposedSnapshot() {
+    return {
+      api_version: apiState.stateResponse?.api_version || apiState.previewResponse?.api_version || "v1",
+      generated_at_millis:
+        apiState.previewResponse?.generated_at_millis ||
+        apiState.stateResponse?.generated_at_millis ||
+        0,
+      state: apiState.stateResponse?.state || null,
+      preview: apiState.previewResponse?.preview || null,
+      catalog: apiState.catalog || null,
+    };
   }
 
   function pushEvent(entry) {
-    apiState.events.unshift(entry);
-    apiState.events = apiState.events.slice(0, 12);
+    apiState.events.unshift({
+      kind: entry.kind || "info",
+      code: entry.code || null,
+      ...entry,
+    });
+    apiState.events = apiState.events.slice(0, 50);
     renderEvents();
   }
 
   function renderEvents() {
-    if (!apiState.events.length) {
-      dom.eventList.innerHTML = '<div class="empty-state">No websocket notices yet.</div>';
+    const kindFilter = dom.eventKindFilter.value;
+    const searchFilter = dom.eventSearchFilter.value.trim().toLowerCase();
+    const filtered = apiState.events.filter((entry) => {
+      const kindMatches = kindFilter === "all" || entry.kind === kindFilter;
+      const searchMatches =
+        !searchFilter ||
+        (entry.message || "").toLowerCase().includes(searchFilter) ||
+        (entry.code || "").toLowerCase().includes(searchFilter);
+      return kindMatches && searchMatches;
+    });
+
+    if (!filtered.length) {
+      dom.eventList.innerHTML = '<div class="empty-state">No events match the current filter.</div>';
       return;
     }
 
-    dom.eventList.innerHTML = apiState.events
+    dom.eventList.innerHTML = filtered
       .map(
         (entry) => `
-          <article class="event-item">
+          <article class="event-item event-${entry.kind}">
             <div class="event-meta">${entry.at}</div>
+            ${entry.code ? `<span class="event-code">${entry.code}</span>` : ""}
             <strong>${entry.message}</strong>
           </article>
         `

web/v1/index.html

@@ -45,11 +45,20 @@
             </label>
 
             <label class="field">
-              <span>Transition</span>
+              <span>Transition Duration</span>
               <input id="transition-slider" type="range" min="0" max="3000" step="10" />
               <strong id="transition-value">0 ms</strong>
             </label>
 
+            <label class="field">
+              <span>Transition Style</span>
+              <select id="transition-style-select">
+                <option value="snap">Snap</option>
+                <option value="crossfade">Crossfade</option>
+                <option value="chase">Chase</option>
+              </select>
+            </label>
+
             <label class="field">
               <span>Master Brightness</span>
               <input id="brightness-slider" type="range" min="0" max="1" step="0.01" />
@@ -72,14 +81,65 @@
             <div id="preset-list" class="pill-row"></div>
           </div>
 
+          <div class="subsection">
+            <div class="subsection-heading">
+              <h3>Preset Capture</h3>
+              <p>Store or overwrite the current scene as a reusable preset through the same API.</p>
+            </div>
+            <div class="capture-grid">
+              <label class="field">
+                <span>Preset ID</span>
+                <input id="preset-id-input" type="text" placeholder="e.g. sunset_chase" />
+              </label>
+              <label class="field inline-checkbox">
+                <span>Overwrite Existing</span>
+                <input id="preset-overwrite-input" type="checkbox" />
+              </label>
+              <button id="save-preset-button" class="ghost-button" type="button">
+                Save Current Scene As Preset
+              </button>
+            </div>
+          </div>
+
           <div class="subsection">
             <div class="subsection-heading">
               <h3>Groups</h3>
               <p>Focus looks on a subset while keeping the core scene model shared.</p>
             </div>
+            <input
+              id="group-filter-input"
+              class="filter-input"
+              type="text"
+              placeholder="Filter groups by id or tag"
+            />
             <div id="group-list" class="pill-row"></div>
           </div>
 
+          <div class="subsection">
+            <div class="subsection-heading">
+              <h3>Creative Snapshots</h3>
+              <p>Capture exploratory variants without replacing curated presets.</p>
+            </div>
+            <div class="capture-grid">
+              <label class="field">
+                <span>Snapshot ID</span>
+                <input id="snapshot-id-input" type="text" placeholder="e.g. variant_afterglow" />
+              </label>
+              <label class="field">
+                <span>Label</span>
+                <input id="snapshot-label-input" type="text" placeholder="Readable label" />
+              </label>
+              <label class="field inline-checkbox">
+                <span>Overwrite Existing</span>
+                <input id="snapshot-overwrite-input" type="checkbox" />
+              </label>
+              <button id="save-snapshot-button" class="ghost-button" type="button">
+                Save Creative Snapshot
+              </button>
+            </div>
+            <div id="snapshot-list" class="snapshot-list"></div>
+          </div>
+
           <div class="subsection">
             <div class="subsection-heading">
               <h3>Scene Parameters</h3>
@@ -111,6 +171,20 @@
             <h2>Event Stream</h2>
             <p>Recent notices from the websocket feed.</p>
           </div>
+          <div class="event-filter-bar">
+            <select id="event-kind-filter">
+              <option value="all">All kinds</option>
+              <option value="info">Info</option>
+              <option value="warning">Warning</option>
+              <option value="error">Error</option>
+            </select>
+            <input
+              id="event-search-filter"
+              class="filter-input"
+              type="text"
+              placeholder="Filter by code or message"
+            />
+          </div>
           <div id="event-list" class="event-list"></div>
         </section>
       </main>

web/v1/styles.css

@@ -202,6 +202,7 @@ body::after {
 }
 
 .control-grid,
+.capture-grid,
 .parameter-grid,
 .summary-cards {
   display: grid;
@@ -212,6 +213,11 @@ body::after {
   grid-template-columns: repeat(2, minmax(0, 1fr));
 }
 
+.capture-grid {
+  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
+  align-items: end;
+}
+
 .parameter-grid,
 .summary-cards {
   grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
@@ -295,11 +301,26 @@ input[type="text"] {
   color: var(--text);
 }
 
+.filter-input {
+  margin-bottom: 12px;
+}
+
 input[type="range"] {
   width: 100%;
   accent-color: var(--accent);
 }
 
+.inline-checkbox {
+  align-content: start;
+}
+
+.inline-checkbox input[type="checkbox"] {
+  width: 20px;
+  height: 20px;
+  margin: 4px 0 0;
+  accent-color: var(--accent-cool);
+}
+
 .ghost-button,
 .preset-button,
 .group-button {
@@ -374,6 +395,21 @@ input[type="range"] {
   box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.32);
 }
 
+.energy-bar {
+  height: 8px;
+  margin-top: 12px;
+  border-radius: 999px;
+  background: rgba(31, 36, 36, 0.08);
+  overflow: hidden;
+}
+
+.energy-bar > span {
+  display: block;
+  height: 100%;
+  width: var(--energy-width, 0%);
+  background: linear-gradient(90deg, var(--preview-color, #999999), rgba(255, 255, 255, 0.84));
+}
+
 .sample-row {
   display: flex;
   flex-wrap: wrap;
@@ -429,11 +465,84 @@ input[type="range"] {
   gap: 12px;
 }
 
+.event-filter-bar {
+  display: grid;
+  grid-template-columns: 180px minmax(0, 1fr);
+  gap: 12px;
+  margin-bottom: 14px;
+}
+
 .event-item {
   display: grid;
   gap: 8px;
 }
 
+.event-item.event-info strong {
+  color: var(--accent-strong);
+}
+
+.event-item.event-warning strong {
+  color: #a7631c;
+}
+
+.event-item.event-error strong {
+  color: var(--danger);
+}
+
+.event-code {
+  display: inline-flex;
+  width: fit-content;
+  padding: 4px 8px;
+  border-radius: 999px;
+  background: rgba(31, 36, 36, 0.08);
+  color: var(--muted);
+  font-size: 0.78rem;
+  letter-spacing: 0.05em;
+  text-transform: uppercase;
+}
+
+.snapshot-list {
+  display: grid;
+  gap: 12px;
+  margin-top: 14px;
+}
+
+.snapshot-card {
+  display: grid;
+  gap: 8px;
+  padding: 14px;
+  border-radius: var(--radius-md);
+  background: var(--surface-strong);
+  border: 1px solid rgba(56, 63, 61, 0.08);
+}
+
+.snapshot-card-header {
+  display: flex;
+  justify-content: space-between;
+  gap: 12px;
+  align-items: start;
+}
+
+.snapshot-card-header strong {
+  display: block;
+  margin-bottom: 2px;
+}
+
+.snapshot-meta-row {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 8px;
+}
+
+.meta-chip {
+  display: inline-flex;
+  padding: 5px 8px;
+  border-radius: 999px;
+  background: rgba(31, 36, 36, 0.08);
+  color: var(--muted);
+  font-size: 0.82rem;
+}
+
 .event-item strong {
   color: var(--accent-strong);
 }
@@ -460,7 +569,8 @@ input[type="range"] {
 @media (max-width: 1080px) {
   .layout,
   .hero,
-  .control-grid {
+  .control-grid,
+  .event-filter-bar {
     grid-template-columns: 1fr;
   }